act

1 of 5

noun

ˈakt 

1

a

: 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

5

a

: 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

act

2 of 5

verb

acted; acting; acts

intransitive verb

1

: to take action : move

think before acting

acted favorably on the recommendation

2

: to conduct oneself : behave

act like a fool

3

a

: 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

1

a

: 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

c

: impersonate

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

actability

ˌak-tə-ˈbi-lə-tē 

noun

actable

ˈak-tə-bəl 

adjective

act

3 of 5

abbreviation (1)

1

active

2

actor

3

actual

ACT

4 of 5

abbreviation (2)

1

Action for Children's Television

2

Association of Classroom Teachers

3

Australian Capital Territory

ACT

5 of 5

trademark

ˌā-ˌsē-ˈtē 

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

Phrases

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

Synonyms

Noun

• bit
• number
• routine
• shtick
• schtick
• shtik
• turn

Verb

• do
• impersonate
• interpret
• perform
• play
• portray

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.

Recent Examples on the Web

Noun

The Kings were back in Edmonton for the third installment of their postseason trilogy Monday and the first act did not go well, with the Oilers scoring twice in the first 10 minutes on their way to a 7-4 win. —Kevin Baxter, Los Angeles Times, 23 Apr. 2024

Other acts on this year’s lineup include Teddy Swims, Slowdive, Killer Mike, TV Girl, Charley Crockett, Men I Trust, Ben Howard, Amyl and the Sniffers, Kevin Abstract, Romy, Badbadnotgood, Strfkr, Corinne Bailey Rae, Snakehips, Allen Stone and more. —Gil Kaufman, Billboard, 23 Apr. 2024

All three acts have gone on to other successes, but this tour brings together the songs and sounds that first brought them to fame. —Jem Aswad, Variety, 23 Apr. 2024

The Supreme Court said Nixon couldn't be sued for official acts. —USA TODAY, 23 Apr. 2024

Israel’s decision to attack Egypt in June 1967 was not only a preemptive strike but also an act of nightmarish panic. —Tom Segev, Foreign Affairs, 23 Apr. 2024

The move could be seen as an act of desperation from Grayscale, the world’s largest crypto asset manager. —Vinamrata Chaturvedi, Quartz, 22 Apr. 2024

Honestly, people engage in this act every single day. —Heide Janssen, Orange County Register, 21 Apr. 2024

The album’s success validated the act — to an extent. —Katie Bain, Billboard, 11 Apr. 2024

Verb

There are classes on acting from Steve Martin and Helen Mirren, on photography from Annie Leibovitz, on music from Ringo Starr, on science and technology from Neil deGrasse Tyson and James Cameron, to name a few. —Claire Peltier, ABC News, 12 Apr. 2024

However, Kathleen Zellner, Avery's defense attorney, has said that new evidence shows Dassey acted alone. —Christina Coulter, Fox News, 12 Apr. 2024

There will be a machine there that the Secret Service said acts like a giant x-ray machine. —Ricardo Torres, Journal Sentinel, 12 Apr. 2024

Read on to see our top bedding picks from Nate Home, but act fast to add them to your cart because inventory is moving fast. —Clara McMahon, Peoplemag, 12 Apr. 2024

Thompson said he’s heard from many parents who have acted on the letters. —Kavitha Cardoza, CNN, 12 Apr. 2024

The slowdown in electric vehicle sales continues to snowball, with plummeting resale values acting as another roadblock. —Medora Lee, USA TODAY, 11 Apr. 2024

Tubulins make up tubular filaments known as microtubules, which act like cells’ skeletons. —Will Sullivan, Smithsonian Magazine, 11 Apr. 2024

This announcement comes about a month after Meghan Markle subtly announced her mysterious new lifestyle brand American Riviera Orchard, which many believe will act as a Goopified version of her old blog, The Tig. —Emily Tannenbaum, Glamour, 11 Apr. 2024

Word History

Etymology

Noun

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

Verb

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

First Known Use

Noun

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

Verb

1590, in the meaning defined at intransitive sense 2

Phrases Containing act

• act accordingly
• act dumb
• act of God
• act one's age
• act on/upon
• act out
• act/play the fool
• act the part
• act up
• a hard/tough act to follow
• balancing act
• caught in the act
• class act
• clean up one's act
• co-act
• get in on the act
• get into the act
• get one's act together
• high-wire act
• in on the act
• in the act (of doing something)
• into the act
• juggling act
• pull a vanishing act
• put on an act
• read the riot act
• riot act
• sex act
• the sex act

Kids Definition

act

1 of 2 noun

ˈakt 

1

: something that is done

an act of kindness

2

: the doing of something

caught in the act

3

: a law made by a governing body

an act of Congress

4

a

: one of the main divisions of a play or opera

b

: one of the parts of a variety show or circus

5

: a display of behavior that is not sincere

just putting on an act

act

2 of 2 verb

1

: to perform by action especially on the stage

2

: to play the part of

act the man of the world

3

a

: to behave in a manner suitable to

act your age

b

: to conduct oneself

act like a fool

4

: to take action : move

think before you act

5

a

: to perform a function : serve

act as mayor

b

: to produce an effect : work

wait for a medicine to act

Etymology

Noun

Middle English act "act, deed," from Latin actus "action of doing" and from Latin actum "something done," both from agere "to drive, do" — related to agent

Medical Definition

act

1 of 3 noun

ˈakt 

1

: a motor performance leading to a definite result

2

: a dealing with objects (as by moving, perceiving, or desiring them)

act

2 of 3 intransitive verb

1

: to perform an act : behave

2

: to produce an effect

wait for a medicine to act

act

3 of 3 abbreviation

active

Legal Definition

act

1 of 2 noun

1

a

: 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

2

a

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 act

—U.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

act

2 of 2 intransitive verb

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 President

—U.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

actor

ˈak-tər 

noun