• enPR: ăkt, IPA: /ækt/
• (AAVE) IPA: /æk/

From Middle English acte, from Old French acte, from Latin ācta, plural of āctum ("decree, law"), from agere, ultimately from Proto-Indo-European *h₂éǵeti.

act

1. (countable) Something done, a deed.

   an act of goodwill

   • 1798, William Wordsworth, Lines:

     That best portion of a good man's life, / His little, nameless, unremembered acts / Of kindness and of love.

2. (obsolete, uncountable) Actuality.
   • 1594–1597, Richard Hooker, edited by J[ohn] S[penser], Of the Lawes of Ecclesiastical Politie, […], London: […] Will[iam] Stansby [for Matthew Lownes], published 1611, →OCLC ↗, (please specify the page):

     The seeds of plants are not at first in act, but in possibility, what they afterward grow to be.

3. (theology) Something done once and for all, as distinguished from a work.
4. (law, countable) A product of a legislative body, a statute.
5. The process of doing something.

   He was caught in the act of stealing.

6. (countable) A formal or official record of something done.
7. (countable, drama) A division of a theatrical performance.
   • 1904–1905, Baroness Orczy [i.e., Emma Orczy], “The Lisson Grove Mystery ↗”, in The Case of Miss Elliott, London: T[homas] Fisher Unwin, published 1905, →OCLC ↗; republished as popular edition, London: Greening & Co., 1909, OCLC 11192831 ↗, quoted in The Case of Miss Elliott (ebook no. 2000141h.html), Australia: Project Gutenberg of Australia, February 2020:

     “H'm !” he said, “so, so—it is a tragedy in a prologue and three acts. I am going down this afternoon to see the curtain fall for the third time on what […] will prove a good burlesque ; but it all began dramatically enough. It was last Saturday […] that two boys, playing in the little spinney just outside Wembley Park Station, came across three large parcels done up in American cloth. […] ”

   The pivotal moment in the play was in the first scene of the second act.

8. (countable) A performer or performers in a show.

   Which act did you prefer? The soloist or the band?

9. (countable) Any organized activity.
10. (countable) A display of behaviour.
    1. (countable) A display of behaviour meant to deceive.

       to put on an act

11. A thesis maintained in public, in some English universities, by a candidate for a degree, or to show the proficiency of a student.
12. (law) Ellipsis of act of parliament

• (something done) deed; see also Thesaurus:action
• (product of a legislative body) statute
• (display of behavior) pretense

• action
• active
• agency
• agent

• French: acte
• German: Handlung, Tat, Akt
• Italian: atto
• Portuguese: ato
• Russian: де́йствие
• Spanish: acto

• French: acte
• Portuguese: ato

• French: loi
• German: Gesetz
• Italian: legge
• Portuguese: lei
• Russian: зако́н
• Spanish: ley

• French: acte, action
• German: Akt, Handlung
• Italian: atto
• Portuguese: ato, ação
• Russian: де́йствие
• Spanish: acto, acción

• French: acte
• German: Akte
• Portuguese: ata
• Russian: акт
• Spanish: hecho

• French: acte
• German: Akt
• Italian: atto, numero
• Portuguese: ato
• Russian: акт
• Spanish: acto

• French: acte
• German: Spiel, Auftreten, Handeln
• Italian: scena, messinscena
• Portuguese: ato
• Russian: игра́

act (acts, present participle acting; simple past and past participle acted)

1. (intransitive) To do something.

   If you don’t act soon, you will be in trouble.

2. (obsolete, transitive) To do (something); to perform.
   • 1651, Jer[emy] Taylor, “Signes of Purity of Intention”, in The Rule and Exercises of Holy Living. […], 2nd edition, London: […] Francis Ashe […], →OCLC ↗, page 23 ↗:

     that we act our temporal affairs with a deſire no greater than our neceſſity

   • a. 1678 (date written), Isaac Barrow, “(please specify the chapter name or sermon number). Of Industry in General”, in The Works of Dr. Isaac Barrow. […], volume (please specify |volume=I to VII), London: A[braham] J[ohn] Valpy, […], published 1830–1831, →OCLC ↗:

     Industry doth beget by producing good habits, and facility of acting things expedient for us to do.

   • 1782, William Cowper, Expostulation:

     Uplifted hands that at convenient times / Could act extortion and the worst of crimes.

3. (intransitive) To perform a theatrical role.

   I started acting at the age of eleven in my local theatre.

4. (intransitive) Of a play: to be acted out (well or badly).
5. (intransitive) To behave in a certain manner for an indefinite length of time.

   A dog which acts aggressively is likely to bite.

   I believe that Bill’s stuck-up because of the way that he acts.

   He’s acting strangely—I think there’s something wrong with him.

6. (copulative) To convey an appearance of being.

   He acted unconcerned so the others wouldn’t worry.

7. (intransitive) To do something that causes a change binding on the doer.

   act on behalf of John

8. (intransitive, construed with on or upon) To have an effect (on).

   High-pressure oxygen acts on the central nervous system and may cause convulsions or death.

   Gravitational force acts on heavy bodies.

9. (transitive) To play (a role).

   He’s been acting Shakespearean leads since he was twelve.

10. (transitive) To feign.

    He acted the angry parent, but was secretly amused.

    • 1697, Virgil, “The Second Book of the Æneis”, in John Dryden, transl., The Works of Virgil: Containing His Pastorals, Georgics, and Æneis. […], London: […] Jacob Tonson, […], →OCLC ↗:

      With acted fear the villain thus pursued.

11. (intransitive, law) To carry out work as a legal representative in relation to a particular legal matter.

    A lawyer cannot act until they have been formally instructed by their client.

12. (intransitive, mathematics, construed with on or upon, of an algebraic structure) To possess an action onto (some other structure). Examples include the group action of a group on a set, the action of a ring on a module by scalar multiplication, and the action of a group or algebra on a vector space via a representation.

    This group acts on the circle, so it can't be left-orderable!

13. (obsolete, transitive) To move to action; to actuate; to animate.
    • 1733, [Alexander Pope], An Essay on Man. […], (please specify |epistle=I to IV), London: Printed for J[ohn] Wilford, […], →OCLC ↗:

      Self-love, the spring of motion, acts the soul.

14. (obsolete, Scotland, transitive) To enact; to decree.

• action
• activate
• active
• deactivate

• French: agir, faire
• German: handeln, tun, machen
• Italian: agire
• Portuguese: agir
• Russian: де́йствовать
• Spanish: actuar

• French: jouer
• German: spielen
• Italian: recitare
• Portuguese: atuar
• Russian: игра́ть
• Spanish: actuar

• French: se comporter
• German: benehmen, verhalten
• Italian: fare, comportarsi
• Portuguese: comportar-se
• Russian: вести
• Spanish: comportar

• German: agieren
• Russian: де́йствовать

• German: wirken, agieren, auswirken
• Italian: attuare, regolare, guidare, governare
• Portuguese: agir (sobre/em)
• Russian: возде́йствовать

act

1. (text messaging) Clipping of actually

   james did u act enjoy that juice? looked like u were gagging icl

1. Initialism of Australian Capital Territory, a federal territory of Australia.

   Coordinate terms: NSW, NT, QLD, SA, TAS, VIC, WA

2. Initialism of w:American College Test
3. Initialism of w:Association of Consumers and Taxpayers, a political party of New Zealand
   1. (New Zealand politics) ACT New Zealand, a liberal conservative political party in New Zealand

act

1. (countable) An instance of a certain standardized college admissions test in the United States, originally called the American College Test.
2. (uncountable) Acronym of acceptance and commitment therapy

act

1. Ellipsis of Act of Parliament