ACT Vocabulary

ACT Top 1000 Vocabulary Words

A complete 1000-word ACT vocabulary list, covering all four Reading passage types, the English section's grammar and style requirements, and the Science section's technical terminology.

1000 words · Words 1–500 + Words 501–1000 · Definitions · ACT-style examples

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What makes the ACT Top 1000 different: The first 500 words cover ACT English and general Reading vocabulary. Words 501–1000 focus on the vocabulary you need to navigate ACT Reading's prose fiction, social science, humanities, and natural science passages at the highest scoring levels — complete literary terms, full ACT Science vocabulary, and advanced academic language.

Words 1–500 (Top 500 Summary)

Words 1–500 are fully detailed on the ACT Top 500 page and include:

Section 1 (1–50): Transition & Connective Words — accordingly, albeit, conversely, furthermore, nevertheless, whereas...

Section 2 (51–100): Commonly Confused Words — affect/effect, imply/infer, who/whom, fewer/less, its/it's...

Section 3 (101–150): Literary & Rhetorical Terms — allusion, anachronism, anaphora, catharsis, denouement...

Section 4 (151–200): Science Passage Vocabulary — catalyst, chromosome, diffusion, equilibrium, photosynthesis...

Section 5 (201–250): Social Studies & History — amendment, democracy, gerrymandering, sovereignty, suffrage...

Section 6 (251–300): Academic English — aberrant, aggregate, copious, cumulative, diligent, empirical...

Section 7 (301–350): Character & Narrative — epiphany, foil, melancholy, pathos, redemption, stoic...

Section 8 (351–400): Argumentation & Logic — assertion, cogent, contention, fallacy, premise, rhetorical...

Section 9 (401–450): Arts & Culture — aesthetic, avant-garde, iconography, patronage, vernacular...

Section 10 (451–500): General Academic Vocabulary — anomalous, causal, correlate, disproportionate, fluctuate...

Words 501–560: Literary Terms — Complete Reference

#	Word	Part of Speech	Definition	ACT-Style Example
501	allegory	noun	A story where characters, events, and settings symbolize abstract ideas or moral qualities.	The passage identifies the work as a political allegory in which each character embodies a different political faction.
502	alliteration	noun	The repetition of the same initial consonant sound in closely associated words.	The author notes the deliberate alliteration in the phrase 'cold, clinging, cheerless' to evoke the bleakness of the setting.
503	allusion	noun	An indirect reference to a well-known person, event, work, or idea.	The novel's title is an allusion to Keats's 'Ode to a Nightingale,' signaling its themes of beauty and transience.
504	anachronism	noun	Something that belongs to a period other than that in which it is represented.	The novel avoids anachronism by confining its characters to technology and language available in 1890.
505	anaphora	noun	The repetition of a word or phrase at the beginning of successive clauses.	The speech's emotional force derives from anaphora: 'We will remember. We will rebuild. We will return.'
506	antagonist	noun	The principal character in opposition to the hero of a narrative.	The antagonist functions not merely as an obstacle but as a mirror of the protagonist's suppressed desires.
507	antithesis	noun	The direct contrast of ideas, usually in parallel grammatical structure.	The antithesis 'Man proposes, God disposes' expresses the limits of human agency.
508	archetype	noun	A universal, recurring symbol, character type, or theme in human storytelling.	The trickster archetype appears across diverse world mythologies, from Anansi to Loki to Coyote.
509	assonance	noun	The repetition of vowel sounds in nearby words, creating internal rhyme.	The assonance in 'the lone stone home' gives the phrase a mournful, resonant quality.
510	catharsis	noun	Emotional purging through art; the release of repressed emotions.	Aristotle's concept of catharsis holds that tragedy allows audiences to safely experience pity and fear.
511	chiasmus	noun	A figure of speech in which grammatical structures are repeated in reverse order.	The chiasmus 'Live not to eat; eat to live' inverts the grammatical structure to sharpen the contrast.
512	climax	noun	The most intense or exciting point in a narrative; the turning point.	The climax arrives in the novel's penultimate chapter, when the protagonist makes the irreversible decision.
513	connotation	noun	The emotional or cultural associations of a word beyond its literal meaning.	Both 'thrifty' and 'miserly' describe someone who spends little, but their connotations differ vastly.
514	denotation	noun	The precise, literal, dictionary meaning of a word.	The denotation of 'willow' is a type of tree, but its connotations include grief and mourning.
515	denouement	noun	The final resolution of a plot, occurring after the climax.	In the denouement, all the novel's loose threads are gathered — not neatly, but honestly.
516	diction	noun	The choice of words and style of expression in writing or speaking.	The author's elevated diction in the opening chapter marks a deliberate distance from the colloquial voice she adopts later.
517	dramatic irony	noun	When the audience knows something the characters do not.	The reader experiences dramatic irony throughout the play, knowing the letter has gone astray while the characters remain ignorant.
518	elegy	noun	A poem or song of lament for the dead; a mournful or plaintive poem.	The passage reads the poem as an elegy not only for the dead friend but for an entire lost generation.
519	epithet	noun	An adjective or phrase expressing a quality of the person or thing; a characterizing word.	Homer's epithets — 'rosy-fingered Dawn,' 'wine-dark sea' — function as mnemonic anchors in oral performance.
520	exposition	noun	Background information provided at the start of a narrative to establish context.	The novel's lengthy exposition risks losing impatient readers but rewards those who persist.
521	extended metaphor	noun	A metaphor sustained throughout a text or a major section of it.	The poem's extended metaphor of weaving — threading, knotting, unraveling — carries the entire argument.
522	flashback	noun	A scene set in a time earlier than the main narrative action.	A flashback to the character's exile reveals the wound that governs every decision she makes in the present.
523	foil	noun	A character who contrasts with another character to highlight particular qualities.	The ambitious younger sibling serves as a foil to the protagonist's deliberate, methodical approach.
524	foreshadowing	noun	Hints or clues about what will happen later in the narrative.	The recurring image of broken mirrors functions as foreshadowing for the family's eventual fracturing.
525	free verse	noun	Poetry that does not follow a fixed meter or rhyme scheme.	The poet chose free verse to allow the form to mirror the unstructured nature of grief.
526	hyperbole	noun	Obvious exaggeration for emphasis or comic effect.	When the narrator says she has 'explained this a thousand times,' she employs hyperbole to express exhaustion.
527	imagery	noun	Language that appeals to the senses; vivid descriptive language.	The poem's imagery — salt air, worn wood, faded photographs — accumulates into a portrait of gentle decay.
528	irony	noun	The expression of meaning through language that normally signifies the opposite.	The deepest irony of the novel is that the character who most values honesty is the one most deceived.
529	juxtaposition	noun	Placing two contrasting elements side by side for effect.	The author's juxtaposition of the child's laugh and the sound of gunfire is the most devastating moment in the novel.
530	lyric poetry	noun	Short, personal poetry that expresses the speaker's feelings and emotions.	The passage distinguishes lyric poetry — focused on inner emotional life — from epic poetry's outward narrative scope.
531	metaphor	noun	A direct comparison between unlike things without using 'like' or 'as.'	The central metaphor of the essay — the city as a living organism — organizes all its arguments.
532	motif	noun	A recurring image, symbol, or theme that carries meaning throughout a work.	The motif of windows — looking in, looking out, glass as barrier — runs through every chapter.
533	narrator	noun	The voice or agent that tells the story.	The narrator's shift from first to second person in the final chapter implicates the reader directly in the story.
534	ode	noun	An elaborately formal lyric poem addressed to and celebrating a person, place, or thing.	The Romantic ode reached its apex in the works of Keats, Shelley, and Wordsworth.
535	onomatopoeia	noun	Words that imitate the sounds they describe.	The poet saturates the battlefield scene with onomatopoeia — 'thud,' 'snap,' 'hiss' — to create immersive sonic violence.
536	oxymoron	noun	A combination of contradictory terms.	The phrase 'bittersweet farewell' is an oxymoron that captures the emotional complexity of the scene.
537	paradox	noun	A statement that seems contradictory but reveals a deeper truth.	The paradox at the heart of the poem — that remembering is a form of forgetting — gives it its aching resonance.
538	persona	noun	The voice or mask assumed by an author or speaker in a literary work.	The detached, clinical persona the author adopts in the memoir keeps the most painful material at a careful distance.
539	personification	noun	Attributing human qualities to non-human things.	The river is personified throughout the novel as a wise elder who watches human folly with weary patience.
540	plot	noun	The sequence of events in a narrative; the causal structure of a story.	The plot follows a classical arc: exposition, rising action, climax, falling action, and resolution.
541	point of view	noun	The perspective from which a story is narrated.	The shift in point of view from first to third person signals the narrator's attempt to distance herself from her own history.
542	protagonist	noun	The main character of a literary work.	The protagonist's central flaw — her inability to ask for help — is established in the novel's first scene.
543	rhetoric	noun	The art of effective persuasion through writing or speech.	The passage analyzes the rhetoric of the speech, identifying the emotional appeals and logical structure.
544	satire	noun	The use of humor, irony, and exaggeration to criticize human vice or folly.	The novel is a biting satire of corporate culture, using absurdity to expose the banality of institutional evil.
545	simile	noun	A comparison using 'like' or 'as.'	The simile 'her thoughts darted like startled fish' captures the chaos of her mental state.
546	soliloquy	noun	A dramatic monologue in which a character reveals inner thoughts while alone on stage.	The protagonist's soliloquy in Act III is the emotional center of the play — a naked confrontation with mortality.
547	sonnet	noun	A 14-line poem with a prescribed rhyme scheme and logical structure.	Shakespeare's sonnets explore the tension between the permanence of art and the transience of human beauty.
548	stream of consciousness	noun	A narrative technique that presents a character's continuous flow of thoughts.	The novel's stream of consciousness technique gives readers direct access to the narrator's uncensored inner life.
549	subtext	noun	The meaning beneath the surface of a text; what is implied but not stated.	The subtext of every exchange between the two characters is their mutual awareness that the relationship is ending.
550	symbol	noun	An object, person, or event that represents something beyond itself.	The green light at the end of the dock functions as a symbol of Gatsby's unreachable aspirations.
551	syntax	noun	The arrangement of words and phrases to form sentences; sentence structure.	The author's fragmented syntax in the final chapter mirrors the disintegration of the narrator's sense of self.
552	theme	noun	The central idea or message of a literary work.	The novel's dominant theme — the cost of silence — is articulated in the epigraph and echoed throughout.
553	tone	noun	The author's attitude toward the subject, conveyed through word choice and style.	The tone shifts from nostalgia to bitterness across the memoir's three sections, mirroring the narrator's aging disillusionment.
554	tragedy	noun	A form of drama ending in the downfall of the protagonist, typically through a fatal flaw.	The play fulfills the conditions of classical tragedy: a noble protagonist brought low by a specific, identifiable flaw.
555	understatement	noun	Presenting something as less important than it is, for rhetorical effect.	Describing the destruction of an entire city as 'a bit unfortunate' is a deliberate understatement that heightens the horror.
556	unreliable narrator	noun	A narrator whose account cannot be fully trusted.	The narrator is unreliable in the most interesting way: not dishonest, but deeply self-deceived.
557	verisimilitude	noun	The appearance of being true or real; lifelike quality in fiction.	The novel achieves verisimilitude through its obsessive attention to period dress, speech, and custom.
558	voice	noun	The distinctive personality and style of a writer, recognizable across their work.	The author's voice — wry, warm, and precise — is immediately identifiable from the opening sentence.
559	volta	noun	A turn or shift in argument, tone, or direction in a poem.	The volta in line 9 transforms the poem from complaint to acceptance in a single breath.
560	zeugma	noun	The use of one word to govern two or more words in different ways.	The sentence 'She lost her patience and her keys' is a zeugma, applying 'lost' in two distinct senses.

Words 561–610: Advanced Literary & Rhetorical Terms

#	Word	Part of Speech	Definition	ACT-Style Example
561	anadiplosis	noun	Repetition of the last word of one clause at the beginning of the next.	The passage notes the anadiplosis: 'Fear leads to anger; anger leads to hatred; hatred leads to conflict.'
562	apostrophe	noun	A rhetorical device in which a speaker addresses an absent person, abstract idea, or object.	The poem uses apostrophe when the speaker directly addresses the dead lover as if she were present.
563	bathos	noun	An abrupt, jarring shift from the sublime to the ridiculous; anticlimax.	The eulogy slides into bathos when the speaker pivots from praising the deceased's courage to praising his sandwiches.
564	bildungsroman	noun	A coming-of-age novel that traces the protagonist's development from youth to maturity.	The novel is a classic bildungsroman: a young woman leaves her small town and is transformed by the wider world.
565	circumlocution	noun	The use of many words where fewer would do; indirect language.	The politician's circumlocution — ten sentences where one would suffice — struck critics as a deliberate evasion.
566	deus ex machina	noun	An unexpected power or event introduced to resolve a plot difficulty.	Critics condemned the ending as a deus ex machina: an improbably convenient inheritance saves the protagonist.
567	didactic	adjective	Intended to convey instruction and information; morally instructive.	The novel's didactic tone alienated some readers who preferred less explicit moral guidance.
568	dystopia	noun	An imagined world in which everything is unpleasant or bad; opposite of utopia.	The passage examines how dystopia as a literary genre reflects contemporary fears about surveillance, conformity, and loss of autonomy.
569	ekphrasis	noun	A vivid, often dramatized description of a work of visual art, used as a literary device.	Keats's 'Ode on a Grecian Urn' is the most celebrated example of ekphrasis in the English tradition.
570	ellipsis	noun	The omission of words from a sentence understood from context; the punctuation mark (...).	The author's use of ellipsis in the dialogue suggests hesitation, incomplete thought, and emotional suppression.
571	enjambment	noun	The continuation of a sentence without a pause beyond the end of a line of poetry.	The enjambment carries the reader forward, refusing closure and mimicking the breathless urgency of the speaker's emotion.
572	epistolary	adjective	Relating to or denoting a literary work written in the form of letters.	The epistolary novel allows the reader to perceive characters through their own words rather than a narrator's interpretation.
573	ethos	noun	An appeal to credibility or ethical character; the characteristic spirit of a culture.	The speaker establishes ethos by citing her twenty years of field research before presenting her claims.
574	euphemism	noun	A mild or indirect word used in place of one that might be offensive or harsh.	The phrase 'passed on' is a euphemism for death that softens a painful reality.
575	existentialism	noun	A philosophical movement holding that individuals create their own meaning in an indifferent universe.	The novel is deeply existentialist: the protagonist must define herself through choices in a world that offers no guidance.
576	frame narrative	noun	A story within a story; an outer narrative that contains one or more inner narratives.	The Decameron and The Canterbury Tales both employ frame narratives to organize their collections of tales.
577	gothic	adjective/noun	A literary genre featuring elements of horror, the supernatural, and psychological terror.	The novel's gothic atmosphere — crumbling manor, unexplained sounds, family secrets — is skillfully maintained throughout.
578	hegemony	noun	Dominance of one culture, class, or group over others; cultural leadership.	The passage examines how literary hegemony determines which voices are heard and which are silenced.
579	hubris	noun	Excessive pride or confidence that leads to downfall.	The tragic hero's hubris — his refusal to accept human limits — makes his fall both inevitable and comprehensible.
580	in medias res	phrase	Beginning a narrative in the middle of the action, without prior exposition.	The novel opens in medias res: the protagonist is already running, and we learn why in fragments over the following chapters.
581	intertextuality	noun	The relationship between texts; the way texts reference and respond to each other.	The passage explores the intertextuality between the two novels, tracing shared images, themes, and even sentences.
582	logos	noun	An appeal to logic or reason in argumentation.	The essay balances pathos with logos, grounding its emotional appeals in statistical evidence.
583	magical realism	noun	A literary style in which magical elements appear in an otherwise realistic setting.	The passage identifies magical realism as the mode in which the village's grief literally shapes the weather.
584	metafiction	noun	Fiction that self-consciously reflects on its own nature as a literary work.	The novel breaks the fourth wall through metafiction: the narrator admits she is a character in a book.
585	mimesis	noun	The imitation or representation of reality in art and literature.	Aristotle's concept of mimesis holds that art achieves its purpose through the faithful representation of nature.
586	modernism	noun	A literary and artistic movement of the early 20th century characterized by experimentation and rejection of traditional forms.	Modernism's break from linear narrative was in part a response to the trauma and disillusionment of World War I.
587	motif	noun	A recurring element or pattern in a work that carries thematic significance.	The recurring motif of mirrors throughout the story signals the protagonist's obsession with self-image and self-deception.
588	naturalism	noun	A literary movement depicting life with scientific objectivity, showing humans shaped by heredity and environment.	Zola's naturalism insists that human behavior can be explained by biological and social determinants, not free will.
589	nihilism	noun	The rejection of all moral and religious principles; the belief that life is meaningless.	The novel's antagonist espouses nihilism, insisting that all social structures are constructs concealing a void.
590	pastoral	adjective/noun	Relating to an idealized portrayal of rural life; a work in this tradition.	The passage critiques the pastoral tradition for romanticizing agricultural labor at the expense of those who perform it.
591	pathos	noun	An appeal to emotion; the quality in a work that evokes sadness or pity.	The pathos of the final scene derives from the child's innocent question about when the father is coming home.
592	peripeteia	noun	A sudden reversal of fortune, especially in a dramatic work.	The peripeteia arrives in Act IV when the hero's trusted advisor is revealed as the architect of his downfall.
593	picaresque	noun/adjective	A genre featuring a roguish, lowborn hero who survives by wit in a corrupt society.	The novel is picaresque in structure, following the protagonist through a series of episodic misadventures.
594	polyphony	noun	The presence of multiple voices or perspectives in a literary work.	Dostoevsky's novels are celebrated for their polyphony — no single voice dominates or settles the central questions.
595	postcolonialism	noun	A field of study examining the cultural, political, and economic legacies of colonialism.	The passage applies a postcolonial lens to analyze how the novel encodes the values of its imperial moment.
596	postmodernism	noun	A literary and artistic movement skeptical of grand narratives and objective truth.	The novel's postmodernism is evident in its refusal of a stable narrator or a single authoritative version of events.
597	prosody	noun	The patterns of rhythm and sound used in poetry; the study of meter.	A close analysis of the poem's prosody reveals a deliberate irregularity in the meter that mirrors the speaker's agitation.
598	realism	noun	The literary attempt to represent life truthfully, without idealization or romanticism.	The shift from romanticism to realism in the Victorian novel reflected the growing influence of empiricism and social science.
599	romanticism	noun	A literary and artistic movement emphasizing emotion, nature, and individual imagination.	Romanticism rejected the Enlightenment's faith in reason, privileging feeling and intuition as paths to truth.
600	semiotics	noun	The study of signs and symbols and their interpretation.	The passage uses semiotics to decode the visual language of the advertisement, revealing its ideological assumptions.
601	surrealism	noun	An artistic movement exploring the unconscious mind through irrational imagery and narrative.	The film's surrealism deliberately prevents the viewer from settling into a comfortable interpretive frame.
602	syllepsis	noun	The use of a word to modify two other words in different senses.	In the phrase 'he took my advice and my wallet,' 'took' operates through syllepsis.
603	synecdoche	noun	A figure of speech where a part represents a whole or a whole represents a part.	Calling manual workers 'hands' is a synecdoche that reduces people to their most economically useful function.
604	utopia	noun	An imagined perfect society or community; an ideal but unrealizable state.	The passage argues that all utopias, however well-intentioned, contain the seeds of their own tyranny.
605	verbal irony	noun	A statement in which the literal meaning differs from the intended meaning.	When the critic calls the performance 'unmissable,' her verbal irony is clear to any reader of her previous reviews.
606	villanelle	noun	A 19-line poem with a specific pattern of rhymes and repetitions.	Dylan Thomas's 'Do Not Go Gentle' is the best-known villanelle in the English language.
607	vignette	noun	A short, evocative scene or description; a brief literary sketch.	The memoir is structured as a series of vignettes, each illuminating a different facet of the author's childhood.
608	wit	noun	Keen intelligence; the ability to combine ideas in a surprising, clever, or amusing way.	The essayist's wit transforms potentially dry material into one of the most entertaining arguments in the collection.
609	worldview	noun	A particular philosophy of life; a comprehensive view of the world.	The novel dramatizes the collision between two incompatible worldviews — one shaped by faith, the other by empirical science.
610	diegesis	noun	The narrative world; the story content as distinct from its presentation.	The narrator is diegetic — she exists within the story world and affects its events.
611	mise en abyme	noun	A technique of placing a miniature copy of the work within the work itself.	The painting within the painting is a mise en abyme: it depicts the same scene as the larger canvas in miniature.

Words 611–720: ACT Science Vocabulary — Complete Reference

#	Word	Part of Speech	Definition	ACT-Style Example
611	abiotic	adjective	Relating to the non-living chemical and physical factors in an environment.	The experiment isolated the effects of abiotic factors — light, temperature, and pH — on plant growth.
612	acceleration	noun	The rate at which velocity changes; a vector quantity with both magnitude and direction.	The graph showed that acceleration peaked in the third second before decreasing as friction became dominant.
613	acid	noun/adjective	A substance with pH below 7; a proton donor in chemical reactions.	The passage asked students to predict whether the solution would be acidic or basic after the reaction.
614	adaptation	noun	A heritable trait that improves an organism's fitness in its environment.	The thick layer of subcutaneous fat is an adaptation that allows the walrus to survive in Arctic waters.
615	allele	noun	One of two or more versions of a gene at a particular locus.	The Punnett square showed the probability of inheriting each allele combination from two heterozygous parents.
616	amplitude	noun	The height of a wave from its equilibrium position to its crest.	Students were asked to compare the amplitude of the sound wave before and after the volume was adjusted.
617	anion	noun	A negatively charged ion, formed by gaining electrons.	Chloride is an anion formed when chlorine gains one electron.
618	atom	noun	The smallest unit of an element that retains its chemical properties.	Each atom of carbon has six protons, which defines it as carbon and distinguishes it from all other elements.
619	base	noun/adjective	A substance with pH above 7; a proton acceptor in chemical reactions.	Sodium hydroxide is a strong base that can neutralize hydrochloric acid to produce water and salt.
620	biome	noun	A large naturally occurring community of flora and fauna occupying a major habitat.	The data compared average annual precipitation across six biomes, from tropical rainforest to desert.
621	catalyst	noun	A substance that increases the rate of a reaction without being consumed.	In the absence of the enzyme catalyst, the reaction would proceed too slowly to sustain life.
622	cell	noun	The basic structural and functional unit of all living organisms.	Students were asked to identify which organelle is responsible for energy production in the cell.
623	chromosome	noun	A thread-like structure of DNA and protein in the cell nucleus carrying genetic information.	Human cells contain 46 chromosomes arranged in 23 pairs.
624	circuit	noun	A complete electrical path through which current can flow.	The diagram showed a series circuit in which removing one bulb would break the entire path.
625	coefficient	noun	A numerical factor in a mathematical expression; the number before a variable.	Balancing the chemical equation required adjusting the coefficients to ensure conservation of mass.
626	combustion	noun	A chemical reaction of a fuel with oxygen that produces heat and light.	The passage explained that complete combustion of methane produces carbon dioxide and water vapor.
627	compound	noun	A pure substance formed from two or more elements in fixed proportions.	Carbon monoxide is a compound that forms when combustion is incomplete due to insufficient oxygen.
628	concentration	noun	The amount of substance dissolved per unit volume of solution.	As the concentration of the enzyme substrate increased, the reaction rate increased until reaching saturation.
629	condensation	noun	The conversion of vapor to liquid; a chemical reaction combining molecules with loss of water.	The passage described condensation of water vapor on cold surfaces as a phase change from gas to liquid.
630	control group	noun	The experimental group not exposed to the independent variable; a baseline for comparison.	The control group received distilled water instead of the treatment solution.
631	convection	noun	The transfer of heat by the movement of heated fluids.	The warm ocean current transferred heat to the atmosphere primarily through convection.
632	correlation	noun	A statistical relationship between two variables.	The passage reported a strong positive correlation (r = 0.89) between ocean temperature and coral bleaching events.
633	covalent bond	noun	A chemical bond in which two atoms share electrons.	Water is held together by covalent bonds between the oxygen and each hydrogen atom.
634	decay	noun/verb	The disintegration of radioactive material; the decomposition of organic matter.	Carbon-14 decay allows scientists to date organic materials up to approximately 50,000 years old.
635	density	noun	Mass per unit volume; how tightly packed particles are in a substance.	The experiment measured the density of each liquid by dividing its mass by its measured volume.
636	dependent variable	noun	The variable being measured in an experiment; the outcome that may change.	In the photosynthesis study, oxygen production rate was the dependent variable.
637	diffusion	noun	Net movement of particles from high to low concentration.	The experiment demonstrated diffusion by placing a dye crystal in still water and observing its spread.
638	DNA	noun	Deoxyribonucleic acid; the molecule carrying genetic information in all living organisms.	The passage described the double helix structure of DNA and how it enables faithful replication.
639	dominant	adjective	In genetics, the allele that is expressed when paired with a recessive allele.	Brown eye color is typically dominant over blue in simple Mendelian inheritance models.
640	ecosystem	noun	All the living organisms and their physical environment in a defined area.	The passage examined how the removal of a keystone predator destabilized the entire ecosystem.
641	electrode	noun	A conductor through which current enters or leaves a solution in electrolysis.	At the cathode electrode, positively charged ions gained electrons and were deposited as metal.
642	electron	noun	A negatively charged subatomic particle orbiting the nucleus of an atom.	During oxidation, atoms lose electrons; during reduction, they gain electrons.
643	element	noun	A pure substance composed of atoms with the same atomic number.	The periodic table organizes elements by atomic number and groups them by chemical properties.
644	endothermic	adjective	Absorbing heat from the surroundings during a reaction.	Ice melting is an endothermic process — it absorbs heat energy from the surrounding environment.
645	enzyme	noun	A biological catalyst that speeds up specific biochemical reactions.	Amylase is an enzyme in saliva that begins breaking down starch into simpler sugars.
646	equilibrium	noun	A state of balance; in chemistry, when forward and reverse reaction rates are equal.	Le Chatelier's principle describes how a system at equilibrium responds to changes in concentration or temperature.
647	erosion	noun	The wearing away of rock or soil by wind, water, ice, or chemical action.	The data showed accelerated erosion in areas where vegetation had been removed by wildfire.
648	evaporation	noun	The conversion of a liquid to a gas at its surface, below boiling point.	The graph showed the rate of evaporation increasing as temperature rose and humidity fell.
649	exothermic	adjective	Releasing heat to the surroundings during a reaction.	Combustion is an exothermic process — it releases energy in the form of heat and light.
650	food web	noun	A complex network of feeding relationships in an ecosystem.	The passage asked students to predict the consequences of removing one species from a simplified food web.
651	force	noun	A push or pull acting on an object; measured in Newtons.	Newton's second law states that force equals mass times acceleration.
652	frequency	noun	The number of oscillations per second in a wave; measured in Hertz.	Higher frequency electromagnetic waves carry more energy but have shorter wavelengths.
653	friction	noun	The resistive force between two surfaces in contact.	The experiment compared the friction coefficients of four different materials using an inclined plane.
654	gene	noun	A segment of DNA encoding a specific protein or functional RNA.	The mutation in the BRCA1 gene significantly increases the risk of certain cancers.
655	genotype	noun	The genetic constitution of an organism; the allele combination it carries.	A heterozygous genotype carries one dominant and one recessive allele for a given trait.
656	gravity	noun	The force of attraction between masses; on Earth, the force pulling objects downward.	Gravity provides the centripetal force that keeps planets in orbit around the Sun.
657	habitat	noun	The natural environment in which an organism lives and reproduces.	Wetland habitats support disproportionately high biodiversity relative to their land area.
658	half-life	noun	The time it takes for half of a radioactive substance to decay.	With a half-life of 5,730 years, carbon-14 can be used to date materials up to about 50,000 years old.
659	homeostasis	noun	The ability of an organism to maintain stable internal conditions.	The human body maintains homeostasis by regulating temperature, blood pressure, and blood glucose.
660	hormone	noun	A chemical messenger produced by endocrine glands that regulates body functions.	Insulin is a hormone produced by the pancreas that regulates the uptake of glucose by cells.
661	hypothesis	noun	A proposed explanation for an observation, testable through experimentation.	The students formulated a hypothesis predicting that warmer water would reduce the solubility of oxygen.
662	independent variable	noun	The variable changed by the experimenter to observe its effect on the dependent variable.	The independent variable was light intensity, adjusted at five levels from 0 to 1000 lux.
663	inertia	noun	The tendency of an object to resist changes in its state of motion.	Newton's first law describes inertia: an object at rest remains at rest unless acted on by a net force.
664	inheritance	noun	The transmission of genetic information from parents to offspring.	Mendelian inheritance predicts the probability of each phenotype in the offspring of two known genotypes.
665	ion	noun	An atom or group of atoms with a net electric charge.	The passage described how ion channels regulate the movement of sodium and potassium across cell membranes.
666	ionic bond	noun	A chemical bond formed by the transfer of electrons from one atom to another.	Sodium chloride is held together by ionic bonds between sodium cations and chloride anions.
667	isotope	noun	An atom of an element with the same number of protons but different number of neutrons.	Uranium-235 and Uranium-238 are isotopes with different numbers of neutrons and different rates of radioactive decay.
668	kinetic energy	noun	Energy possessed by an object due to its motion.	As the pendulum swings downward, potential energy is converted to kinetic energy.
669	mass	noun	The amount of matter in an object; measured in kilograms.	Unlike weight, mass does not change with gravitational force.
670	membrane	noun	A thin, selective barrier that controls the passage of substances.	The cell membrane is a selectively permeable phospholipid bilayer that regulates what enters and exits the cell.
671	metabolism	noun	The chemical processes that sustain life in an organism.	The study measured how resting metabolic rate changes with body mass across species of different sizes.
672	mitosis	noun	Cell division that produces two genetically identical daughter cells.	The stages of mitosis — prophase, metaphase, anaphase, telophase — were depicted in the diagram.
673	momentum	noun	The product of an object's mass and velocity; a conserved quantity in isolated systems.	The collision experiment demonstrated the conservation of momentum.
674	mutation	noun	A change in the sequence of DNA that may alter gene expression.	A point mutation changes a single nucleotide and may have no effect, reduce fitness, or occasionally improve it.
675	natural selection	noun	The process by which organisms better adapted to their environment survive and reproduce more.	Natural selection acts on heritable variation, gradually shifting the distribution of traits in a population.
676	neutron	noun	An uncharged subatomic particle in the atomic nucleus.	Adding a neutron to an atom produces a different isotope without changing the element's identity.
677	nucleus	noun	The central part of an atom containing protons and neutrons; the control center of a cell.	The nucleus of the atom was discovered through Rutherford's gold foil experiment.
678	organelle	noun	A specialized structure within a cell with a specific function.	The mitochondrion is the organelle responsible for producing ATP through cellular respiration.
679	osmosis	noun	The movement of water across a semipermeable membrane from low to high solute concentration.	The experiment demonstrated osmosis by measuring the change in mass of potato slices in solutions of different concentrations.
680	oxidation	noun	The loss of electrons by an atom or molecule; a reaction with oxygen.	Rusting is the oxidation of iron in the presence of oxygen and moisture.
681	pH	noun	A scale measuring hydrogen ion concentration; a measure of acidity or alkalinity.	The experiment measured pH changes in the solution as increasing amounts of acid were added.
682	phenotype	noun	The observable characteristics of an organism, resulting from gene-environment interaction.	Eye color is a phenotype that results from the interaction of multiple genes.
683	photosynthesis	noun	The process by which plants convert light energy into chemical energy stored as glucose.	The rate of photosynthesis was measured by counting oxygen bubbles produced per minute at different light intensities.
684	pollination	noun	The transfer of pollen to a plant's stigma, enabling fertilization.	The passage described three mechanisms of pollination: wind, water, and animal vectors.
685	population	noun	A group of organisms of the same species living in a defined area.	The study tracked changes in the predator population over twenty years following the reintroduction program.
686	potential energy	noun	Stored energy due to an object's position or state.	A stretched spring has elastic potential energy that is released when it returns to its natural length.
687	proton	noun	A positively charged subatomic particle in the atomic nucleus.	The atomic number of an element equals the number of protons in its nucleus.
688	protein	noun	A large biomolecule made of amino acids that performs structural and catalytic roles.	Hemoglobin is a protein that transports oxygen in the blood through its iron-containing heme groups.
689	radiation	noun	Energy transmitted as waves or particles; a form of heat transfer.	The passage compared the rates of energy transfer through conduction, convection, and radiation.
690	reaction rate	noun	The speed at which reactants are converted to products in a chemical reaction.	Increasing temperature typically increases reaction rate by providing more activation energy.
691	recessive	adjective	In genetics, an allele expressed only when two copies are present.	Cystic fibrosis is caused by a recessive allele — both parents must be carriers for a child to inherit the disease.
692	refraction	noun	The bending of waves as they pass from one medium to another.	The passage used refraction to explain why a pool appears shallower than it actually is.
693	resistance	noun	Opposition to the flow of electric current; opposition to a drug or disease.	Antibiotic resistance has developed in bacterial populations through natural selection for resistant strains.
694	respiration	noun	The metabolic process by which organisms produce energy from glucose.	In the absence of oxygen, cells switch from aerobic respiration to less efficient anaerobic respiration.
695	solubility	noun	The ability of a substance to dissolve in a solvent; the maximum amount that can dissolve.	The graph showed that solubility of most solids increases with temperature, while gas solubility decreases.
696	solvent	noun	The dissolving substance in a solution, present in greater quantity.	Water is called the universal solvent because of its ability to dissolve a wider range of substances than any other liquid.
697	spectrum	noun	A range of radiation arranged by wavelength; the visible colors of light.	A prism separates white light into its component spectrum of colors from red to violet.
698	synthesis	noun	The production of a chemical compound from simpler materials.	The passage described the synthesis of aspirin as an example of an esterification reaction.
699	temperature	noun	A measure of thermal energy; how hot or cold an object or environment is.	All four experiments were conducted at a controlled temperature of 25°C.
700	terminal velocity	noun	The constant speed a falling object reaches when drag equals gravitational force.	The experiment simulated terminal velocity using coffee filters dropped in a column of air.
701	transpiration	noun	The evaporation of water from plant surfaces, particularly leaves.	Transpiration creates the tension that pulls water from roots to leaves through the xylem.
702	velocity	noun	Speed in a specified direction; a vector quantity.	The slope of the position-time graph equals the object's velocity at any given instant.
703	viscosity	noun	The resistance of a fluid to flowing; internal friction in a fluid.	Honey has a much higher viscosity than water, as demonstrated by its slower flow rate at the same temperature.
704	voltage	noun	The difference in electric potential between two points; electromotive force.	Students were asked to calculate the voltage across each resistor in a parallel circuit.
705	wavelength	noun	The distance between successive crests of a wave.	Gamma rays have shorter wavelengths and higher energy than visible light or radio waves.
706	work	noun	In physics, force times displacement in the direction of the force.	The passage defined work as the product of force and distance traveled in the direction of the force.

Words 721–820: Social Studies — Complete Reference

#	Word	Part of Speech	Definition	ACT-Style Example
721	absolutism	noun	A political system in which a single ruler holds unlimited power.	Louis XIV's court at Versailles symbolized the absolutism of the French monarchy before the Revolution.
722	amendment	noun	A formal change to a legislative document, especially a constitution.	The 19th Amendment extended voting rights to women in 1920, nearly a century after the Seneca Falls Declaration.
723	anarchy	noun	A state of disorder due to the absence or failure of authority.	The passage argued that social contract theory emerged specifically to explain how societies escape the anarchy of the state of nature.
724	annexation	noun	The formal incorporation of a territory into a country or state.	The annexation of Hawaii in 1898 was controversial and remains a contested historical and legal question.
725	aristocracy	noun	Government by a privileged ruling class; that ruling class.	The passage traced how the landed aristocracy gradually ceded political power to industrial capitalists over the 19th century.
726	assimilation	noun	The process by which a minority group adopts the culture of the dominant group.	Government policies in the early 20th century forced assimilation of indigenous children through residential schools.
727	autocracy	noun	A system of government with a single person possessing unrestricted power.	The passage compared the internal governance of three historical autocracies.
728	bicameral	adjective	Having two legislative chambers.	The United States has a bicameral legislature consisting of the Senate and the House of Representatives.
729	bureaucracy	noun	A system of government with complex procedures and many levels of authority.	Weber identified bureaucracy as the defining form of administration in modern societies.
730	capitalism	noun	An economic system based on private ownership and free market exchange.	The passage analyzed capitalism's capacity for creative destruction — generating growth while disrupting established industries.
731	census	noun	An official count of a population, typically including demographic data.	The 2020 census revealed significant population shifts from the Rust Belt to the Sun Belt.
732	checks and balances	noun	A system preventing any one branch of government from becoming too powerful.	The passage examined how checks and balances prevent the concentration of power in the executive branch.
733	civic	adjective	Relating to citizenship, the city, or public life.	Civic participation — voting, community organizing, jury duty — is the foundation of democratic health.
734	civil disobedience	noun	The refusal to comply with laws considered unjust, as a form of political protest.	The passage traced the philosophy of civil disobedience from Thoreau to Gandhi to the American civil rights movement.
735	civil rights	noun	The rights of citizens to political and social freedom and equality.	The Civil Rights Act of 1964 prohibited discrimination based on race, color, religion, sex, or national origin.
736	coalition	noun	A temporary alliance of political parties or groups.	The bill passed only after the formation of a broad coalition that crossed traditional party lines.
737	colonialism	noun	The policy of establishing colonies and exploiting their resources.	The passage analyzed how colonialism's economic extraction shaped contemporary disparities in global wealth.
738	communism	noun	A political and economic system in which the state controls the means of production.	The passage compared how communism was implemented in the Soviet Union and China, noting significant differences.
739	confederation	noun	A union of states with a weak central government.	The Articles of Confederation created a loose confederation that proved too weak to govern effectively.
740	congress	noun	A legislative body, especially that of the United States.	Congress holds the power to declare war, levy taxes, and regulate interstate commerce.
741	conservatism	noun	Political support for traditional institutions and resistance to rapid change.	The passage traced how American conservatism shifted from its Burkean roots to its contemporary populist form.
742	constitution	noun	A body of fundamental principles by which a state is governed.	The constitution established a federal structure, dividing sovereignty between the national and state governments.
743	coup	noun	A sudden seizure of power, especially from a government.	The military coup dissolved the legislature and suspended the constitution indefinitely.
744	democracy	noun	A system of government by the whole population, typically through elected representatives.	Direct democracy, practiced in ancient Athens, differs fundamentally from the representative democracy of modern states.
745	demographic	noun/adjective	Statistics relating to a population; relating to such statistics.	The demographic shift toward an older population has profound implications for healthcare costs and pension solvency.
746	deregulation	noun	The removal of government regulations from an industry.	The passage debated whether deregulation of the financial sector contributed to the 2008 economic crisis.
747	dictatorship	noun	Government by a single person with absolute power.	The passage examined the conditions under which democracies become dictatorships.
748	diplomacy	noun	The management of international relations through negotiation.	The ambassador was credited with the most skillful piece of diplomacy in the region's recent history.
749	discrimination	noun	Unfair treatment based on characteristics such as race, sex, or religion.	The landmark legislation prohibited employment discrimination and created an enforcement mechanism.
750	disenfranchisement	noun	The state of being deprived of the right to vote or civil rights.	The passage examined the systematic disenfranchisement of Black voters through poll taxes and literacy tests.
751	due process	noun	The fair treatment of a person by a court of law; the right to legal procedures.	The Fifth and Fourteenth Amendments guarantee that no person shall be deprived of rights without due process of law.
752	egalitarianism	noun	Belief in equal rights and opportunities for all people.	The passage traced the influence of Enlightenment egalitarianism on the Declaration of Independence.
753	electoral college	noun	The body that formally elects the President of the United States.	The passage examined the historical rationale for the Electoral College and contemporary arguments for and against it.
754	eminent domain	noun	The government's right to take private property for public use with compensation.	The city invoked eminent domain to acquire the land needed for the new public transit corridor.
755	emigration	noun	The act of leaving one's country to settle in another.	The Great Migration involved the emigration of millions of Black Americans from the South to northern cities.
756	enfranchise	verb	To grant the right to vote; to give full rights of citizenship.	The 15th Amendment enfranchised Black American men, though systematic suppression of their votes continued for decades.
757	enlightenment	noun	An 18th-century intellectual movement emphasizing reason, science, and individual rights.	The Enlightenment provided the philosophical foundations for the American and French Revolutions.
758	executive branch	noun	The branch of government responsible for implementing and enforcing laws.	The executive branch is headed by the President, who has broad discretion over foreign policy.
759	fascism	noun	An authoritarian, ultranationalist political ideology marked by dictatorial power.	The passage traced fascism's rise in interwar Europe as a response to economic crisis and perceived national humiliation.
760	federalism	noun	A system of government dividing power between central and regional authorities.	The passage examined the tensions in American federalism between national authority and states' rights.
761	geopolitics	noun	The influence of geography on politics, especially international relations.	The passage argued that access to oil remains the defining geopolitical factor in Middle Eastern foreign policy.
762	globalization	noun	The process of increased interconnection and integration of economies, cultures, and governments.	Globalization has reduced manufacturing costs while accelerating the spread of environmental damage across borders.
763	gross domestic product	noun	The total value of goods and services produced in a country in a given period.	The passage compared the gross domestic product growth rates of emerging and developed economies over two decades.
764	impeachment	noun	The process of charging a public official with misconduct.	The passage described impeachment as the legislature's primary check on executive power.
765	imperialism	noun	A policy of extending power and influence through colonization or military force.	American imperialism in the late 19th century brought Hawaii, Puerto Rico, and the Philippines under US control.
766	infrastructure	noun	The basic physical systems of a country or organization.	Decades of underinvestment in infrastructure have left the nation's bridges and water systems in disrepair.
767	isolationism	noun	A foreign policy of non-involvement in the affairs of other countries.	The passage traced the decline of isolationism following the attack on Pearl Harbor.
768	judicial review	noun	The power of courts to assess laws and executive actions against the constitution.	Marbury v. Madison established the Supreme Court's power of judicial review.
769	judiciary	noun	The branch of government that interprets laws; the court system.	An independent judiciary is considered essential to the rule of law in democratic societies.
770	laissez-faire	adjective	Relating to non-intervention by government in economic affairs.	The laissez-faire policies of the 1920s contributed to the speculative bubble that preceded the Great Depression.
771	legislature	noun	The body of elected representatives empowered to make laws.	The legislature passed the bill by a two-thirds majority, overriding the governor's veto.
772	liberalism	noun	A political philosophy favoring individual rights, democratic governance, and social progress.	Classical liberalism's emphasis on individual liberty differs from modern progressivism's focus on collective welfare.
773	lobbying	noun	Attempts to influence legislators or officials on behalf of an interest group.	The passage described how pharmaceutical lobbying shaped the final version of the healthcare bill.
774	manifest destiny	noun	The 19th-century belief that the United States was destined to expand across North America.	Manifest destiny provided ideological justification for western expansion and the displacement of indigenous peoples.
775	mercantilism	noun	An economic theory holding that national wealth is best increased by exporting more than importing.	Mercantilism led European powers to treat their colonies primarily as sources of raw materials.
776	monarchy	noun	A form of government with a monarch as its head.	The passage traced the evolution of the British monarchy from absolute rule to constitutional constraint.
777	nationalism	noun	Identification with and devotion to the interests of one's nation; a movement for national independence.	Ethnic nationalism in the late 19th and early 20th centuries contributed to the conditions that produced World War I.
778	nullification	noun	A state's refusal to recognize or enforce a federal law it deems unconstitutional.	The nullification crisis of 1832 raised fundamental questions about the relationship between federal and state authority.
779	oligarchy	noun	Government by a small, elite group.	The passage analyzed how market economies can drift toward oligarchy when wealth concentrates sufficiently.
780	ordinance	noun	An authoritative order or law issued by a local government.	The ordinance prohibited plastic bags at retailers larger than a defined threshold.
781	partisan	adjective	Prejudiced in favor of a particular political party or cause.	The passage lamented the increasingly partisan nature of legislative debate, in which party loyalty trumps evidence.
782	propaganda	noun	Biased information used to promote a political cause or point of view.	The passage analyzed how totalitarian governments used film, radio, and posters as propaganda tools.
783	ratification	noun	Formal approval and adoption of a law, treaty, or agreement.	Ratification required approval by three-fourths of the states, making constitutional amendments deliberately difficult.
784	recession	noun	A period of temporary economic decline; two consecutive quarters of negative GDP growth.	The passage analyzed the policy responses to the most recent recession and their differential effects by income level.
785	redistribution	noun	The transfer of income, wealth, or resources from one group to another, typically through taxation.	The passage debated whether income redistribution is more effectively achieved through taxes or targeted spending.
786	referendum	noun	A general vote by citizens on a specific question.	The referendum on constitutional reform attracted unusually high turnout, particularly among young voters.
787	republic	noun	A state in which power is held by elected representatives, not a monarch.	The United States was designed as a constitutional republic in which majority rule is constrained by individual rights.
788	revolution	noun	A forcible overthrow of a government; a fundamental change in political organization.	The French Revolution dismantled the old social order with a speed and violence that shocked Europe.
789	secession	noun	The formal withdrawal from a federation or union.	The Confederate secession prompted a constitutional crisis over whether states had the legal right to leave the Union.
790	segregation	noun	Enforced separation of different groups, typically on grounds of race.	The Supreme Court's 1954 Brown decision declared racially segregated schools unconstitutional.
791	separation of powers	noun	The division of governmental authority among executive, legislative, and judicial branches.	The passage explained how the separation of powers prevents the concentration of authority in any one branch.
792	socialism	noun	A political and economic system in which the means of production are collectively owned.	The passage compared the economic outcomes of different forms of democratic socialism across northern European states.
793	sovereignty	noun	Supreme authority within a territory.	Indigenous sovereignty claims rest on the legal and moral argument that native peoples retain rights to self-governance.
794	subsidy	noun	Financial assistance given by a government to support an industry or activity.	The passage questioned whether agricultural subsidies primarily benefit small family farms or large agribusinesses.
795	suffrage	noun	The right to vote in political elections.	The suffrage movement in the United States spanned more than 70 years before the 19th Amendment was ratified.
796	tariff	noun	A tax on imported or exported goods.	Protective tariffs were intended to shield domestic manufacturers from cheaper foreign competition.
797	totalitarianism	noun	A system of government requiring complete subservience to the state.	The passage compared the mechanisms of control used by totalitarian regimes in the 20th century.
798	treaty	noun	A formally concluded agreement between states.	The passage examined how the treaty's ambiguous language created a century of disputes over territorial rights.
799	tyranny	noun	Cruel and oppressive government or rule.	The Founders designed the Constitution specifically to prevent the tyranny they associated with concentrated power.
800	urbanization	noun	The process by which populations shift from rural to urban areas.	The rapid urbanization of the 20th century transformed both the physical and social landscape of developing nations.
801	veto	noun/verb	The power to reject legislation; to exercise that power.	The president's veto was overridden when Congress secured the required two-thirds majority.
802	welfare state	noun	A system in which the government provides economic protection for its citizens.	The passage compared the structure and cost of the welfare state across OECD countries.

Words 821–900: ACT Reading Academic Vocabulary

#	Word	Part of Speech	Definition	ACT-Style Example
821	accentuate	verb	To make more noticeable or prominent; to emphasize.	The author accentuates the contrast between the two characters by describing them in adjacent paragraphs.
822	acquiesce	verb	To accept something reluctantly but without protest.	The scientist acquiesced to peer pressure and removed the most controversial finding from the published paper.
823	admonish	verb	To warn or reprimand firmly; to urge someone strongly.	The editorial admonishes policymakers to act before the crisis becomes irreversible.
824	affirmation	noun	A statement or proposition that is declared to be true.	The essay closes with an affirmation of the value of democratic institutions despite their imperfections.
825	ameliorate	verb	To make something bad or unsatisfactory better.	The organization's primary goal was to ameliorate the living conditions of displaced families.
826	ambivalence	noun	Having mixed or contradictory feelings about something.	The narrator's ambivalence toward her homeland — longing for it, yet unable to return — pervades every chapter.
827	anecdotal	adjective	Based on personal accounts rather than systematic evidence.	The passage notes that the evidence is largely anecdotal and calls for controlled studies.
828	antagonism	noun	Active hostility or opposition; conflict between forces.	The passage traces the antagonism between the two scientific schools of thought over a period of fifty years.
829	apprehension	noun	Anxiety or fear about a future event; understanding.	The author conveys the child's apprehension about the first day of school through careful attention to small physical details.
830	ardent	adjective	Very enthusiastic or passionate.	An ardent conservationist, the author has spent three decades documenting the transformation of Pacific coastlines.
831	articulate	verb/adjective	To express clearly; having or showing the ability to speak fluently.	The passage articulates three competing theories and evaluates the evidence for each.
832	aspiration	noun	A hope or ambition of achieving something.	The memoir traces how the author's aspirations were shaped and reshaped by forces beyond her control.
833	astute	adjective	Having or showing an ability to assess situations and turn them to one's advantage.	The astute reader will notice that the narrator's account changes subtly between the first and second tellings.
834	augment	verb	To increase or make larger; to supplement.	The new satellite data significantly augment the existing record of ocean temperature changes.
835	autonomy	noun	The right or condition of self-governance; independence.	The passage argues that individual autonomy must be balanced against collective responsibility.
836	bolster	verb	To support or strengthen; to prop up.	The newly released documents bolster the argument that the decision was made for economic rather than strategic reasons.
837	candid	adjective	Truthful and straightforward; frank.	The memoir is unusually candid about the author's failures, which makes it more convincing in its moments of self-praise.
838	capitalize	verb	To take advantage of; to provide with capital; to write in capital letters.	The passage describes how early filmmakers capitalized on the new medium before its conventions had been established.
839	circumspect	adjective	Wary and unwilling to take risks; careful.	The circumspect scientist refused to draw conclusions from a single preliminary study.
840	coerce	verb	To persuade someone to do something by using force or threats.	The passage examines whether economic necessity coerces workers into accepting unsafe conditions.
841	compel	verb	To force or powerfully motivate; to produce an irresistible urge.	The evidence presented in the final section compels the reader toward the author's conclusion.
842	complacent	adjective	Smugly satisfied with oneself or one's achievements; uncritically content.	The passage warns against complacency, arguing that the absence of crisis does not indicate the absence of risk.
843	concise	adjective	Giving a lot of information clearly in a few words; brief but comprehensive.	The most effective ACT responses are concise — they make the point without redundancy.
844	confer	verb	To grant; to have a discussion; to bestow.	A doctoral degree is conferred only after the candidate has successfully defended their dissertation.
845	confound	verb	To surprise and confuse; in research, to be an uncontrolled variable that distorts results.	The results were confounded by the fact that participants in the two groups differed in age.
846	conjecture	noun/verb	An opinion without proof; to form an opinion based on incomplete information.	The passage distinguishes between what the evidence establishes and what remains conjecture.
847	consolidate	verb	To combine into a single more effective or coherent whole.	The revised edition consolidates the three earlier volumes into a single, more navigable reference.
848	contemplate	verb	To think about deeply; to look at thoughtfully.	The narrator spends the novel's middle section contemplating whether her initial judgment was fair.
849	contend	verb	To struggle against; to assert or argue.	The author contends that the policy's failure was predictable given the data available at the time.
850	contradict	verb	To assert the opposite of; to be in conflict with.	The new findings contradict the received wisdom that stress always impairs cognitive performance.
851	controversy	noun	Prolonged public disagreement about a subject.	The controversy over the study's methodology overshadowed its genuinely important findings.
852	conviction	noun	A firmly held belief; a formal declaration of guilt.	The author writes with the conviction of someone who has spent a lifetime studying the question.
853	corroborate	verb	To confirm or give support to a statement or evidence.	The archaeological findings corroborate the written accounts that historians had long considered unreliable.
854	credulous	adjective	Too willing to believe things; gullible.	The narrator describes himself as having been credulous in his youth — willing to accept almost any promise at face value.
855	critical	adjective	Expressing disapproval; finding fault; of crucial importance; using careful analysis.	A critical reading reveals that the passage's conclusion does not follow logically from its premises.
856	defiance	noun	Open resistance or bold disobedience.	The novel's hero acts in deliberate defiance of the rules, which the author presents as both courageous and reckless.
857	deliberation	noun	Long and careful consideration; the process of thinking something through.	The committee's deliberation stretched over three months before producing a consensus recommendation.
858	depict	verb	To show or represent in a picture or description.	The poem depicts winter not as death but as a period of quiet, necessary preparation.
859	derive	verb	To obtain from a source; to develop by reasoning.	The moral framework the author proposes is derived from a combination of utilitarian and rights-based thinking.
860	despondent	adjective	In low spirits; dejected; hopeless.	The narrator's despondent tone in the final chapter contrasts sharply with the energy of the opening.
861	diminish	verb	To make or become less; to reduce in importance.	The author argues that bureaucratic caution can diminish the pace and ambition of scientific discovery.
862	discrepancy	noun	A lack of compatibility between facts or claims.	The passage identifies a discrepancy between the study's stated methodology and what was actually done.
863	disdain	noun/verb	Contempt or lack of respect; to regard with contempt.	The author's disdain for sentimentality is evident in her spare, unadorned prose style.
864	dismiss	verb	To treat as unworthy of consideration; to send away.	The scientist dismissed the anomalous results too quickly, a decision she later acknowledged as a mistake.
865	elaborate	verb/adjective	To add more detail; involving many carefully arranged parts.	The author elaborates her central argument in the third section by introducing comparative data from four countries.
866	elusive	adjective	Difficult to find, catch, or achieve; hard to define or describe.	A precise definition of 'creativity' remains elusive despite decades of psychological research.
867	emerge	verb	To become apparent or prominent; to come out of a difficult situation.	A surprising consensus is beginning to emerge from the competing research programs in the field.
868	empathy	noun	The ability to understand and share another's feelings.	The novelist's greatest talent is her ability to generate genuine empathy for characters who might otherwise seem unsympathetic.
869	equivocal	adjective	Open to more than one interpretation; ambiguous, often deliberately.	The official's equivocal response was interpreted as tacit endorsement by both supporters and opponents.
870	evoke	verb	To bring to mind; to draw out an emotional response.	The author's prose evokes the sensory world of childhood with unusual vividness and precision.
871	exacerbate	verb	To make a problem, situation, or feeling worse.	The passage argues that austerity measures exacerbated the recession by reducing demand.
872	exhaustive	adjective	Including all possible details; thorough.	The bibliography is exhaustive, citing more than 400 sources across six languages.
873	explicit	adjective	Stated clearly and in detail; leaving nothing implied.	The passage is explicit about the study's limitations, which lends the conclusions greater credibility.
874	facilitate	verb	To make an action or process easier.	Improved digital infrastructure has facilitated the spread of information to previously isolated communities.
875	fervent	adjective	Having or displaying a passionate intensity.	The activist's fervent advocacy drew admirers and critics in roughly equal numbers.
876	formulate	verb	To create or prepare methodically; to express in a systematic form.	The researchers formulated their hypothesis based on ten years of preliminary observation.
877	fundamental	adjective	Forming a necessary base; of central importance.	The passage identifies three fundamental assumptions underlying the dominant theory.
878	generate	verb	To produce; to bring about.	The study generated more questions than it answered, which the authors considered a mark of its success.
879	highlight	verb	To emphasize; to pick out as important.	The passage highlights three case studies that support the broader argument.
880	hypothesize	verb	To propose a hypothesis; to speculate based on limited evidence.	The researchers hypothesized that the observed effect was mediated by a specific neurotransmitter pathway.
881	identify	verb	To establish the identity of; to recognize and name.	The passage asks readers to identify the author's primary rhetorical strategy in the opening paragraphs.
882	illustrate	verb	To clarify by using examples or images.	The passage illustrates the principle with a detailed historical case study.
883	impact	noun/verb	A strong effect; to have a strong effect on.	The study assessed the long-term impact of early childhood intervention on adult outcomes.
884	implement	verb	To put a decision or plan into effect.	The school began to implement the new curriculum in stages, starting with the freshman class.
885	implicit	adjective	Suggested but not directly expressed; understood though not stated.	The implicit assumption throughout the passage is that economic efficiency is the primary goal of policy.
886	indicate	verb	To point out; to suggest; to be a sign of.	The data indicate a significant improvement in outcomes following the intervention.
887	inherent	adjective	Existing in something as a permanent or essential attribute.	The passage argues that there is an inherent tension between efficiency and equity in market systems.
888	innovative	adjective	Featuring new methods; introducing novel ideas.	The most innovative aspect of the study was its use of satellite imagery to track changes over 50 years.
889	integrate	verb	To combine one thing with another; to bring different groups together.	The author attempts to integrate insights from economics, sociology, and psychology into a unified framework.
890	interpret	verb	To explain or understand in a particular way; to translate.	The passage interprets the poem's recurring water imagery as a meditation on the nature of memory.
891	justify	verb	To show or prove to be right or reasonable.	The author must justify the dramatic claims in the introduction before the reader will accept the conclusion.
892	logical	adjective	Characterized by clear, sound reasoning.	The essay's structure is logical: it moves from premise to evidence to conclusion without digression.
893	maintain	verb	To keep in an existing state; to assert or affirm.	The author maintains throughout the passage that institutional inertia is the primary obstacle to reform.

Words 901–1000: Advanced Academic Vocabulary

#	Word	Part of Speech	Definition	ACT-Style Example
901	abstract	verb	To extract; to consider something independently of its associations.	It is impossible to fully abstract the text from the political context in which it was produced.
902	acumen	noun	Keenness and quickness of judgment in a particular domain.	The investor's financial acumen allowed her to identify overvalued assets before the broader market recognized them.
903	advocate	noun/verb	One who supports a cause; to publicly recommend.	The passage advocates for a more patient-centered approach to chronic disease management.
904	affinity	noun	A natural liking or attraction to something; a close resemblance.	The author's prose reveals an affinity for the precise, unadorned language of scientific reporting.
905	agenda	noun	A list of items to be discussed; a set of underlying aims.	The passage warns that conflating scientific findings with policy prescriptions can reveal an ideological agenda.
906	alacrity	noun	Brisk and cheerful readiness.	The team responded with alacrity to the unexpected funding opportunity, submitting the proposal within 48 hours.
907	anomaly	noun	Something that deviates from the standard or expected; an irregularity.	The single anomaly in an otherwise consistent dataset prompted a complete re-examination of the methodology.
908	antecedent	noun	A thing that comes before or precedes; in grammar, the noun a pronoun refers to.	The passage traces the intellectual antecedents of modern behavioral economics.
909	appease	verb	To pacify by conceding demands; to relieve tension.	The partial concession was designed to appease critics without fundamentally altering the policy.
910	articulate	verb/adjective	To express thoughts clearly; having the ability to speak and express ideas clearly.	The passage is most effective when its ideas are most concisely and articulately expressed.
911	assiduous	adjective	Showing great care and perseverance; hardworking.	The historian's assiduous research uncovered documents that had not been examined in over a century.
912	atrophy	verb/noun	To waste away from lack of use; the process of such decay.	Language skills atrophy without regular practice, a fact the passage uses to argue for sustained instruction.
913	audacity	noun	The willingness to take bold risks; insolent boldness.	The researcher's audacity — challenging a paradigm that had stood for fifty years — was not universally appreciated.
914	authentic	adjective	Genuine; not copied; representing true feelings.	The passage argues that authentic leadership requires transparency about uncertainty and limitation.
915	autonomy	noun	Self-governance; independence from external control.	The debate over professional autonomy versus institutional oversight applies equally to medicine, law, and education.
916	axiom	noun	A statement accepted as true without proof; a self-evident truth.	The passage challenges the axiom that more information always leads to better decisions.
917	benevolent	adjective	Well-meaning and kindly; charitable.	The essay questions the assumption that benevolent intentions guarantee beneficial outcomes.
918	candor	noun	The quality of being open and honest in expression.	The author's candor about her own biases makes her argument more, not less, persuasive.
919	catalyst	noun	A person or event that causes or accelerates change.	The publication proved to be a catalyst for the broader reform movement that followed.
920	causality	noun	The relationship between cause and effect.	The passage emphasizes that establishing causality requires more than observing correlation.
921	circuitous	adjective	Longer and less direct than necessary; indirect.	The essay's circuitous structure — wandering through digressions before arriving at its point — tests readers' patience.
922	cogent	adjective	Clear, logical, and convincing.	The most cogent objection to the proposal is that it will disproportionately burden low-income households.
923	cognizant	adjective	Having knowledge of; aware of.	A responsible writer is cognizant of how word choice can reinforce or challenge cultural assumptions.
924	coherence	noun	The quality of being logical and consistent; unity.	The essay's coherence is achieved through consistent use of a central metaphor.
925	commensurate	adjective	Corresponding in size or degree; proportionate.	The passage argues that responsibility without commensurate authority is a recipe for ineffective governance.
926	concede	verb	To admit or acknowledge; to yield.	Even the author's sharpest critics concede the elegance of her core argument.
927	conceptualize	verb	To form a concept or idea of; to understand in abstract terms.	The challenge is to conceptualize a policy framework that accommodates both efficiency and equity.
928	conclusive	adjective	Decisive; ending doubt or dispute.	No single study provides conclusive evidence; the strength of the claim depends on the cumulative literature.
929	condone	verb	To accept and allow behavior that is considered immoral or wrong.	The passage argues that inaction on climate change condones the displacement of future generations.
930	congruent	adjective	In agreement or harmony; identical in form.	The author's stated values appear congruent with the choices she made throughout her career.
931	conscientious	adjective	Wishing to do what is right; diligent and thorough.	A conscientious scientist documents every step of the experimental procedure, including failures.
932	considerable	adjective	Notably large in size, extent, or importance.	The study devotes considerable attention to the cases that do not fit the dominant pattern.
933	constitutive	adjective	Having the power to establish or give organized existence to something; formative.	The passage argues that language is constitutive of thought, not merely its vehicle.
934	contingent	adjective	Subject to chance; dependent on circumstances not yet determined.	The success of the program is contingent on continued funding, which is not guaranteed.
935	controversial	adjective	Giving rise to public disagreement; disputed.	The passage makes a deliberately controversial claim to provoke serious engagement with the question.
936	conviction	noun	A firmly held belief; certainty.	The author writes with the conviction of someone who has spent years studying the evidence.
937	counterintuitive	adjective	Contrary to intuition; opposite of what common sense would suggest.	The counterintuitive finding — that more transparency can reduce trust — is one the passage explores at length.
938	credibility	noun	The quality of being trusted and believed.	The author's credibility is established early by the depth and breadth of her citations.
939	criteria	noun	Principles or standards by which things are judged.	The passage establishes three criteria for evaluating competing explanations of the same phenomenon.
940	cursory	adjective	Hasty and not thorough; rapid and superficial.	Even a cursory examination of the data reveals that the sample is not representative.
941	dearth	noun	A scarcity or lack of something.	The passage identifies a dearth of longitudinal studies as the primary limitation of current research.
942	deference	noun	Humble submission and respect; yielding to another's judgment.	In deference to the community's concerns, the planners modified the original proposal.
943	deliberate	adjective	Done intentionally; careful and considered.	The passage's structure is deliberate — each section builds on the previous to create a cumulative argument.
944	dichotomy	noun	A division into two mutually exclusive categories.	The passage rejects the simple dichotomy between nature and nurture as a false binary.
945	differentiate	verb	To recognize or express a difference; to distinguish.	A sophisticated argument must differentiate between correlation, causation, and coincidence.
946	dilemma	noun	A situation requiring a choice between equally undesirable options.	The dilemma at the heart of the passage is whether to prioritize individual freedom or collective safety.
947	disingenuous	adjective	Not candid; not straightforward; insincere.	The reviewer found the author's claim of neutrality disingenuous given her extensive advocacy record.
948	disposition	noun	A tendency or inclination to behave in a particular way; character.	A scientific disposition requires holding conclusions tentatively, pending better evidence.
949	dissent	noun/verb	Disagreement with official or prevailing opinion.	The lone dissenting voice in the study — a junior researcher — was ultimately vindicated when the results were reanalyzed.
950	divergent	adjective	Tending to be different; not consistent.	The two experiments produced divergent results that could not be reconciled with the current theoretical framework.
951	doctrine	noun	A set of beliefs held by an organization; an official policy.	The passage examines the historical development of the doctrine of judicial review.
952	dogmatic	adjective	Inclined to lay down principles as incontrovertibly true; asserting opinions as absolute truth.	The scientist's dogmatic commitment to the original hypothesis prevented her from seeing what the data actually showed.
953	dominant	adjective	Most important or influential; most prevalent.	The dominant explanation in the literature was challenged by the new findings.
954	dynamic	adjective/noun	Characterized by continuous change; a force that produces change.	The dynamic between economic growth and environmental protection is the central tension of the passage.
955	eccentric	adjective	Unconventional and slightly strange; departing from convention.	The eccentric theorist's ideas were ridiculed for years before becoming foundational to the discipline.
956	efficacy	noun	The ability to produce a desired or intended result.	The clinical trial was designed to assess the efficacy and safety of the new treatment.
957	elaborate	verb/adjective	To develop in detail; intricate and complex.	The final section elaborates on the policy implications suggested in the introduction.
958	elicit	verb	To draw out a response or reaction; to evoke.	The question was designed to elicit responses that revealed participants' underlying assumptions.
959	empiricism	noun	The theory that knowledge is derived primarily from sensory experience and observation.	Bacon's empiricism was a foundational element of the Scientific Revolution's method.
960	endorse	verb	To publicly approve or recommend.	The research community has not yet endorsed the new classification, pending peer review.
961	enumerate	verb	To list; to count or establish one by one.	The passage enumerates five distinct objections to the policy before addressing each in turn.
962	ephemeral	adjective	Lasting for a very short time; transitory.	The passage contrasts the ephemeral nature of digital communication with the durability of printed text.
963	equitable	adjective	Fair and impartial; treating all parties equally.	The passage argues that an equitable distribution of resources does not require identical outcomes.
964	erudite	adjective	Having or showing great learning or knowledge.	The erudite essayist draws connections between molecular biology and medieval philosophy that few readers could anticipate.
965	ethical	adjective	Relating to moral principles; morally correct.	The passage examines the ethical dimensions of research involving human subjects.
966	exacerbate	verb	To make worse or more severe.	Cutting public transit funding exacerbates inequality by removing affordable transportation from low-income communities.
967	exhaustive	adjective	Including all possible detail; thorough and comprehensive.	The exhaustive analysis covers every hypothesis proposed in the literature over the past thirty years.
968	explicit	adjective	Stated clearly and in detail; not implicit.	The policy's goals should be explicit rather than buried in administrative guidance documents.
969	facilitate	verb	To make easier; to help bring about.	The program was designed to facilitate collaboration between researchers who had never previously worked together.
970	fallacious	adjective	Based on a mistaken belief; containing a fallacy.	The argument is fallacious: it assumes that the exception disproves the rule.
971	fervent	adjective	Having or displaying strong feeling; intensely enthusiastic.	The fervent opening of the essay gives way to a more measured, analytical tone as the argument develops.
972	formidable	adjective	Inspiring fear or respect through being impressively large or powerful.	The reformers faced a formidable coalition of opponents who stood to lose from any change in the existing system.
973	frugal	adjective	Sparing or economical with regard to money or resources.	The study was conducted on a frugal budget, which required creative solutions to resource constraints.
974	fundamental	adjective	Serving as an essential base; primary.	The passage identifies three fundamental flaws in the dominant theoretical framework.
975	generate	verb	To produce; to bring into existence.	The controversial paper generated an unusually large volume of responses in the letters section.
976	genuine	adjective	Truly what it is said to be; authentic; sincere.	The passage calls for genuine dialogue between the two research communities rather than mutual dismissal.
977	gratuitous	adjective	Uncalled for; not necessary; done without good reason.	The reviewer found the personal attack gratuitous and unrelated to the substantive argument.
978	gravity	noun	Extreme seriousness; importance; also, the force of attraction between masses.	The passage conveys the gravity of the ecological crisis without resorting to sensationalism.
979	guile	noun	Sly or cunning intelligence; deceitfulness.	The character's guile is presented not as an inherent flaw but as a survival skill developed under oppression.
980	hierarchy	noun	A system of organization in which people have different ranks or levels of importance.	The passage questions whether hierarchies in academic institutions facilitate or obstruct the creation of knowledge.
981	homogeneous	adjective	Of the same kind; lacking diversity.	The study's sample was homogeneous, which limits the generalizability of its findings.
982	hypothesis	noun	A proposed explanation serving as a starting point for further investigation.	The competing hypotheses each account for part of the evidence, but none accounts for all of it.

How to use the ACT Top 1000

Start with literary terms

The complete literary terms section (501–560) is essential for the ACT Reading prose fiction passage. Know these terms before the test.

Read the science vocabulary in context

Don't memorize science definitions in isolation. Instead, read each example sentence and picture the graph or experiment described.

Use the social studies words for dual-passage questions

ACT Reading's paired passage set often involves social studies or history. The political vocabulary at 721–820 helps you track complex arguments.

Apply advanced academic words to tone questions

ACT Reading frequently asks about the author's tone, purpose, and attitude. The advanced academic vocabulary at 821–1000 gives you the precision to choose the right answer.

Master 3000 words for maximum ACT readiness

The ACT Top 3000 extends coverage with advanced literary and rhetorical vocabulary, AP-level science and social studies terminology, and commonly tested idioms — in a compact, fast-scanning format.

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