\ 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

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

Keep scrolling for more

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

Visit the Thesaurus for More 

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.
See More
Recent Examples on the Web: Noun Civil violations of the act are handled by an independent agency known as the Office of Special Counsel. New York Times, "Can America Restore the Rule of Law Without Prosecuting Trump?," 18 Nov. 2020 Higgins is charged with material support of an act of terrorism, a 20-year felony. Joe Guillen, Detroit Free Press, "Wisconsin defendant in Whitmer kidnap plot plans to fight his extradition to Michigan," 18 Nov. 2020 In the absence of an official White House comment, Chatterjee, a former energy adviser to Senate Majority Leader Mitch McConnell, has cast his demotion as an act of retaliation against him for moving to address climate change. Josh Siegel, Washington Examiner, "White House says it skipped announcement of Chatterjee demotion at FERC to avoid 'embarrassing' him," 16 Nov. 2020 You might be tempted to stay up late as an act of agency. Lily Janiak,, "Biden won the election, but doomscrolling is here to stay," 14 Nov. 2020 On June 25, 2013, the court declared that Sections 4(b) and 5 of the act were unconstitutional, relaxing federal oversight of jurisdictions with a history of voter suppression. Washington Post, "This D.C. man fights to educate Americans on the importance of voting," 2 Nov. 2020 Ohioans should be aware of the act, considering its passage came largely on the heels of a national uproar over the Cuyahoga River catching fire. cleveland, "Coronavirus has dominated the election. But what happens on the other important issues if Biden or Trump wins? Analysis," 25 Oct. 2020 Several people snapped photos of Maloy's act, sending them onto the sheriff's office. Fox News, "Maryland police officer praised for simple act of kindness, 'example of professionalism'," 20 Oct. 2020 This is a difficult case, largely due to the senseless nature of the act. Jack Greiner, The Enquirer, "Strictly Legal: Facebook avoids liability for horrific death," 20 Oct. 2020 Recent Examples on the Web: Verb The law appropriated funds to act as loss-absorbing buffers that enabled the Fed to stabilize financial markets and make loans to companies and municipal debt issuers. Christopher Condon,, "Fed to Return Lending Backstop Funds to Treasury as Requested," 20 Nov. 2020 However, bioethicist Michelle McGowan at Cincinnati Children’s Hospital Medical Center in Ohio, who studies health care equity, believes the federal government is better positioned to act as an honest broker. Sarah Elizabeth Richards, Wired, "One Man’s Search for the DNA Data That Could Save His Life," 19 Nov. 2020 Talk turned to the fact that many American Legion and VFW posts as well as the likes of the Elks Club and Moose Lodge effectively act as restaurants and have been hurt by the pandemic. Bob Blubaugh,, "Carroll County expands coronavirus relief funding to service organizations with restaurants, service-oriented businesses," 19 Nov. 2020 There, every woman over the age of 25 in our social circles took it upon herself to act as my surrogate older sister, including one who saw no problem with reading my then-confidential diary. Alexis Okeowo, Vogue, "Family Values: An Ode to Aunties and Their Inimitable Sense of Style," 19 Nov. 2020 Amid the chaos of 2020, the Rockefeller Center Christmas tree arrived in New York City this week to act as a beacon of light, shining some hope on an otherwise very tough year. Sophie Lewis, CBS News, "Tiny owl rescued from Rockefeller Center Christmas tree after 3 days without food or water," 19 Nov. 2020 The mask comes with a nose wire across the top and is made with two layers, which create a space to insert a disposable mask inside to act as a filter. Emily Vanschmus, Better Homes & Gardens, "8 Christmas Face Masks That’ll Make You Feel Holly Jolly This Season," 18 Nov. 2020 The website, called CopWatch, is meant to act as a a clearinghouse for public information about San Francisco’s law enforcement agencies. Megan Cassidy,, "S.F. Public Defender’s Office launches website for searching cop records," 18 Nov. 2020 Cano served an 80-game suspension in 2018, his final year with the Seattle Mariners, after testing positive for furosemide, a diuretic that can act as a masking agent when used in conjunction with performance-enhancing drugs. Bill Shaikin, Los Angeles Times, "Robinson Cano suspended for 2021 season after positive drug test," 18 Nov. 2020

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.

See More

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

Keep scrolling for more

Learn More about act

Time Traveler for act

Time Traveler

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

See more words from the same century

Statistics for act

Last Updated

22 Nov 2020

Cite this Entry

“Act.” Dictionary, Merriam-Webster, Accessed 28 Nov. 2020.

Keep scrolling for more

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)


Keep scrolling for more



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

Keep scrolling for more

More from Merriam-Webster on act

Thesaurus: All synonyms and antonyms for act

Nglish: Translation of act for Spanish Speakers

Britannica English: Translation of act for Arabic Speakers

Comments on act

What made you want to look up act? Please tell us where you read or heard it (including the quote, if possible).


Test Your Vocabulary

A Thanksgiving Word Quiz

  • a traditional thanksgiving dinner
  • November comes from a word for which of the following numbers?
Spell It

Can you spell these 10 commonly misspelled words?

Add Diction

Test Your Knowledge - and learn some interesting things along the way.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!