\ ˈakt How to pronounce act (audio) \

Essential Meaning of act

1 : something that is done His first official act [=action] as President was to sign the bill. We were grateful for her many acts of kindness. See More Examplesan act of bravery = a brave act criminal/illegal/unlawful/wrongful actsHide
2 : a law made by a group of legislators The program was created by (an) act of Congress/Parliament. legislative acts the Civil Rights Act of 1964
3 : one of the main divisions of a play or opera Please read act II, scene 1 of Shakespeare's Romeo and Juliet. In the first/opening act, two characters are talking in a restaurant. a play in three acts = a three-act play

Full 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

Definition of act (Entry 3 of 5)

1 active
2 actor
3 actual

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 ACT (audio) \ noun
actable \ ˈak-​tə-​bəl How to pronounce ACT (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 This is a time when people try to make amends and many participate in additional Tzedakah (the act of giving to those in need). Emily Vanschmus, Better Homes & Gardens, 8 Sep. 2021 The first national park, Yellowstone — larger than the states of Rhode Island and Delaware combined — was established by an act of Congress signed by President Ulysses S. Grant on March 1, 1872. Joy Wallace Dickinson,, 7 Sep. 2021 In the dining room, Noguchi paper lanterns hang above a bété wood table of Giacolette’s design; nearby, salvaged iron grates act as room dividers. New York Times, 7 Sep. 2021 Levinsky says that process starts with regret for wrongdoing, continues with identifying the cause inside oneself for the act, and apologizing to and making amends to the person offended. The Salt Lake Tribune, 5 Sep. 2021 This simple act, motivated by compassion and amity, often leads to disaster and heartache. James Berman, Forbes, 3 Sep. 2021 Not an easy act to follow, and harder still for someone who has yet to throw his first pass in a collegiate game. Nathan Baird, cleveland, 31 Aug. 2021 Mullins is the first act to play Infinity Hall Hartford since the spring of 2020 on Sunday, 30 Front St., Hartford. Christopher Arnott,, 29 Aug. 2021 The project to honor the veterans was created by an act of Congress. oregonlive, 22 Aug. 2021 Recent Examples on the Web: Verb The state Legislature would have to act before Friday’s close of session to keep the COVID sick-leave policy alive. Aidin Vaziri, San Francisco Chronicle, 8 Sep. 2021 Get yourself out there, and then figure out where and how to act. Paul Blanchard, Rolling Stone, 1 Sep. 2021 Several more high profile critics launched their ire at the Supreme Court, which has yet to act on an emergency appeal to put the law on hold. Fox News, 1 Sep. 2021 But repeatedly extending the federal moratorium removed any incentive that states had to act with dispatch. Joel Zinberg, National Review, 31 Aug. 2021 There's a lot of handwringing about how machines will behave when faced with ethical scenarios, yet there's no consistency on how humans behave or even how they're supposed to act. Debarshi Chaudhury, Forbes, 30 Aug. 2021 Faced with a threat, the brain has to act fast, its neurons making new connections to learn what might spell the difference between life and death. Quanta Magazine, 30 Aug. 2021 And these days, journalists often have to act much like spies to escape prosecution of whistleblowers and leakers. Jacob Silverman, The New Republic, 18 Aug. 2021 The second thing that's important is the FDA has to act. Kimani Hayes, CBS News, 8 Aug. 2021

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

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

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Last Updated

11 Sep 2021

Cite this Entry

“Act.” Dictionary, Merriam-Webster, Accessed 19 Sep. 2021.

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More Definitions for act


\ 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)


intransitive verb

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)




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


intransitive verb

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 act (audio) \ noun

More from Merriam-Webster on act

Nglish: Translation of act for Spanish Speakers

Britannica English: Translation of act for Arabic Speakers


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