\ ˈakt How to pronounce act (audio) \

Definition of act

 (Entry 1 of 5)

1a : the doing of a thing : deed an act of courage
b law : something done voluntarily
2 : the process of doing something : action caught in the act
3 : the formal product of a legislative body : statute an act of Congress also : a decision or determination of a sovereign, a legislative council, or a court of justice
4 : one of the principal divisions of a theatrical work (such as a play or opera) a play in three acts
5a : one of successive parts or performances (as in a variety show or circus) a magic act
b : the performer or performers in such an act a two-person comedy act
c : a performance or presentation identified with a particular individual or group They took their act on the road.
d : the sum of a person's actions or effects that serve to create an impression or set an example a hard act to follow
6 : a display of affected behavior : pretense put on an act that deceived nobody His friendly concern was just an act.
7 often capitalized : a formal record of something done or transacted
8 : a state of real existence rather than possibility
into the act or in on the act
: into an undertaking or situation as an active participant saw the success they were having and wanted to get in on the act


acted; acting; acts

Definition of act (Entry 2 of 5)

intransitive verb

1 : to take action : move think before acting acted favorably on the recommendation
2 : to conduct oneself : behave act like a fool
3a : to perform on the stage began acting at the age of eight
b : to behave as if performing on the stage : pretend seemed angry but was just acting
4 : to perform a specified function : serve trees acting as a windbreak
5 : to produce an effect : work wait for a medicine to act
6 : to give a decision or award adjourned without acting on the bill
7 of a play : to be capable of being performed a play that acts well

transitive verb

1a : to represent or perform by action especially on the stage will act the part of Romeo in tonight's play
b : feign, simulate act indifference
2 : to play the part of as if in a play act the man of the world
3 : to behave in a manner suitable to Act your age.
4 obsolete : actuate, animate


abbreviation (1)

Definition of act (Entry 3 of 5)

1 active
2 actor
3 actual


abbreviation (2)

Definition of ACT (Entry 4 of 5)

1 Action for Children's Television
2 Association of Classroom Teachers
3 Australian Capital Territory
\ ˌā-ˌsē-ˈtē How to pronounce ACT (audio) \

Definition of ACT (Entry 5 of 5)

used for a standardized achievement test to evaluate suitability for college admission

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Other Words from act


actability \ ˌak-​tə-​ˈbi-​lə-​tē How to pronounce actability (audio) \ noun
actable \ ˈak-​tə-​bəl How to pronounce actable (audio) \ adjective

Synonyms for act

Synonyms: Noun

Synonyms: Verb

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Examples of act in a Sentence

Noun We were grateful for her many acts of kindness. the Civil Rights Act of 1964 Please read act II, scene 1 of Shakespeare's Romeo and Juliet. In the first act, two characters are talking in a restaurant. Verb He knew he had to act quickly. The government was slow to act. She acted on behalf of her father, who was not at the meeting. I believe that the killer acted alone. She had acted in self-defense when she killed her attacker. We were acting in the best interests of our children. We must act soon to end this crisis. She learned at an early age how to act properly in social situations. People are always telling me how I should act and what I should say. I noticed that the dog was acting funny this morning.
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Recent Examples on the Web: Noun In the meantime, Gilead is still piecing together its third act. Damian Garde, STAT, "Gilead CEO Daniel O’Day says company is in an ‘acquisitive mode’," 20 Nov. 2019 Only this second act has a few complications not experienced in the recovery that ended with the iconic 2nd-and-26 final bow. Michael Casagrande |, al, "Making sense of snake bit Alabama’s season of bizarre injuries, why it’s not like 2017," 19 Nov. 2019 Who knows whether WeWork will pull its act together, but the brush with death came a bit too much out of the blue. Wired, "Every Startup Needs to Prepare for Its Downfall," 19 Nov. 2019 Muller said Hastings’ outstanding dedication to the Katy through his selfless acts shows him to be a shining example of the type of person the lodge seeks to honor. Karen Zurawski, Houston Chronicle, "Katy Masonic Lodge honors mayor for service," 19 Nov. 2019 Here, breakout star Josh O’Connor talks to about portraying the longest-waiting heir in history and what’s in store for his next act. Erica Gonzales, Harper's BAZAAR, "The breakout star explains Charles’s investiture, Camilla Shand relationship, and tensions with the queen in Season 3.," 18 Nov. 2019 Don ArnoldGetty Images In her latest act of charitable goodness, Katie Holmes traveled to Sydney, Australia to volunteer with Ronald McDonald House for McHappy Day. Kayleigh Roberts, Marie Claire, "Katie Holmes Spent the Weekend Playing with Koala Bears and I Can Barely Handle It," 17 Nov. 2019 Verlander continued a marvelous second act to his career since a 2017 trade from Detroit to Houston., "Jacob deGrom," 14 Nov. 2019 Verlander continued a marvelous second act to his career since a 2017 trade from Detroit to Houston. Jake Seiner, The Denver Post, "Astros’ Verlander, Mets’ deGrom win 2nd Cy Young Awards," 14 Nov. 2019 Recent Examples on the Web: Verb Instead, acts like Lizzo, BJ the Chicago Kid, PJ Morton and Anderson .Paak were overloaded with multiple R&B nominations. Washington Post, "15 Grammy facts: Michelle Obama in, Bruce Springsteen out," 20 Nov. 2019 The Tsunami Stage hosted house acts like Justin Martin, Prok + Fitch, J. Worra, Gorgon City and Dom Dolla, as cool blue lights depicted the visuals of rushing waters. Megan Venzin, Billboard, "Brace For Impact: A Definitive Ranking of the Sonic Activity at Austin's Seismic Dance Event," 20 Nov. 2019 Over time, the gravitational pull is toward acting like rude New York City bus drivers. Jon Caldara, The Denver Post, "Caldara: A little competition would help RTD’s driver shortage," 19 Nov. 2019 And it’s beautifully done, beautifully written, beautifully acted. . Caroline Hallemann, Town & Country, "Did Princess Anne Really Sleep with Camilla's First Husband, Andrew Parker Bowles?," 18 Nov. 2019 While Samuel West went to Oxford to study English literature in the mid-80s, acting was ultimately his calling. Bianca Rodriguez, Marie Claire, "Who Was Sir Anthony Blunt, the Queen's "Art Advisor"?," 17 Nov. 2019 Pay special attention to any new hire that uses pity or acting like a victim to influence you to keep him or her. Dr. Daneen Skube,, "Don’t ignore red flags of new hire; end it now," 14 Nov. 2019 The concrete, which is heated, acts like a heating pad and slowly releases it over time. Evan Frank, Milwaukee Journal Sentinel, "The CEO of Spancrete partnered with his business to transform his 1842 Delafield home," 11 Nov. 2019 The Peroni x Jonathan Adler bar cart is available for purchase for a limited time only, so act fast. Monique Valeris, ELLE Decor, "Jonathan Adler Teams Up with Peroni on a Luxurious Bar Cart," 5 Nov. 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'act.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of act


14th century, in the meaning defined at sense 1a


1590, in the meaning defined at intransitive sense 2

History and Etymology for act


Middle English acte, borrowed from Anglo-French & Latin; Anglo-French acte, act, borrowed partly from Latin āctus "driving of cattle, track for cattle, movement, activity, performance, part of a play" (action noun from agere "to drive (cattle), cause to move, do"), partly from Latin āctum (usually in plural) "thing done, public transaction, record," from neuter of āctus, past participle of agere — more at agent


Middle English acten "to act upon, adjudicate," in part derivative of act act entry 1, in part borrowed from Latin āctus, past participle of agere

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Time Traveler for act

Time Traveler

The first known use of act was in the 14th century

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Statistics for act

Last Updated

26 Nov 2019

Cite this Entry

“Act.” The Dictionary, Merriam-Webster Inc., Accessed 9 December 2019.

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More Definitions for act


How to pronounce ACT (audio)

English Language Learners Definition of act

 (Entry 1 of 2)

: something that is done
: a law made by a group of legislators
: one of the main divisions of a play or opera



English Language Learners Definition of act (Entry 2 of 2)

: to do something : to take action
: to behave in a particular way
: to behave in a way that is not sincere or honest


\ ˈakt How to pronounce act (audio) \

Kids Definition of act

 (Entry 1 of 2)

1 : something that is done : deed an act of bravery
2 : a law made by a governing body
3 : a main division of a play
4 : one of the performances in a show a juggling act
5 : an insincere way of behaving Her crying was just an act.


acted; acting

Kids Definition of act (Entry 2 of 2)

1 : to do something : move It's important to act quickly in an emergency.
2 : to behave oneself in a certain way He's been acting strangely.
3 : to perform as a character in a play Both stars agreed to act in the movie.
4 : to perform a certain function She'll act as our guide.
5 : to have a result : make something happen : work The medicine acts on the heart.
act up
: to behave badly


\ ˈakt How to pronounce act (audio) \

Medical Definition of act

 (Entry 1 of 3)

1 : a motor performance leading to a definite result
2 : a dealing with objects (as by moving, perceiving, or desiring them)

Medical Definition of act (Entry 2 of 3)

1 : to perform an act : behave
2 : to produce an effect wait for a medicine to act

Medical Definition of act (Entry 3 of 3)


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Legal Definition of act

 (Entry 1 of 2)

1a : something done by a person in accordance with his or her free will a tortious act — see also actus reus
b : the failure to do something that one has a legal duty to do

called also negative act

2a often capitalized : the formal product of a legislative body : the formally declared will of a legislature the final requirement of which is usually the signature of the proper executive officer : statute an act of Congress in furtherance of the purposes…of that actU.S. Code
b : a decision or determination of a sovereign, a legislative council, or a court of justice — compare bill sense 1
3 often capitalized : a formal record of something done or transacted given as my free act and deed

Legal Definition of act (Entry 2 of 2)

1 : to carry into effect a determination of the will : take action
2 : to discharge the duties of a specified office or post : perform a specified function used with a prepositional phrase declaring what officer shall then act as PresidentU.S. Constitution art. II
3 : to give a decision or award (as by vote of a deliberative body or by judicial decree) often used with on adjourned with several important matters still not acted on

Other Words from act

actor \ ˈak-​tər How to pronounce actor (audio) \ noun

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More from Merriam-Webster on act

Thesaurus: All synonyms and antonyms for act

Rhyming Dictionary: Words that rhyme with act

Spanish Central: Translation of act

Nglish: Translation of act for Spanish Speakers

Britannica English: Translation of act for Arabic Speakers

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