Meaning & use
act
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Meanings
nouncountable
A single thing done by someone; a deed or action.
Grammar: Plural acts; often followed by of: an act of kindness.
Patterns
- an act of kindness
- commit an act
- every act
Helping the injured bird was a simple act of kindness.
No single act can repair the damage, but each one helps.
nouncountablelegallaw
A law formally approved by a parliament, congress, or similar lawmaking body.
Grammar: Often capitalized in titles: the Civil Rights Act; takes a singular verb when naming one law.
Patterns
- pass an act
- Act of Parliament
- under an act
Parliament passed an act to limit river pollution.
The new act takes effect next spring.
nouncountablemusicsport
One of the main divisions of a play, opera, ballet, or other staged performance.
Grammar: Plural acts; often numbered: Act Two; distinct from a short scene inside it.
Patterns
- Act One
- final act
- act of a play
The first act ends when the sisters discover the letter.
During the final act, the stage went dark.
verbintransitive
To do something, or to behave in a stated way, especially in response to events.
Grammar: No object; followed by adverbs or prepositions: act quickly, act on advice.
Patterns
- act quickly
- act on advice
- act responsibly
The guide told us to act calmly if the dog approaches.
The committee will act on the complaint within a week.
verbtransitive or intransitive
To perform a role in theater, film, television, or a similar production.
Grammar: Can take an object: act the scene; no object: act in films.
Patterns
- act in a play
- act the part
- act on stage
She began to act in community theater at fifteen.
He acted the tired father so convincingly that we laughed.
Word forms
| third person singular | acts |
|---|---|
| past tense | acted |
| past participle | acted |
| -ing form | acting |
Common combinations
- act of kindness
- A small act of kindness can change someones day.
- act on advice
- She decided to act on her doctors advice.
- act responsibly
- Drivers must act responsibly in bad weather.
Synonyms and how they differ
- deed
- Deed is slightly formal and often moral or notable; act is the everyday word.
- action
- Action can be uncountable and broader; act is one countable event.
- statute
- Statute is a formal synonym for a written law; act is common in names of laws.
Opposites
Word family
Commonly confused: act or action? act or law?
act vs action
Action often names doing in general; act is one countable deed or a division of a play.
act vs law
Law is the general system; an act is one formally passed law.
Practice
Choose the correct completion: The council will ______ the report next month.
Choose one answer.
Act on means respond to information or advice. Act of is a noun phrase, and act as means serve as something.
Make it your own
Write a sentence using “act”, then check it and compare it with the examples above.