The Collaborative International Dictionary of English v.0.48:

Act \Act\, v. t. [imp. & p. p. Acted; p. pr. & vb. n.
   Acting.] [L. actus, p. p. of agere to drive, lead, do; but
   influenced by E. act, n.]
   1. To move to action; to actuate; to animate. [Obs.]
      [1913 Webster]

            Self-love, the spring of motion, acts the soul.
                                                  --Pope.
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   2. To perform; to execute; to do. [Archaic]
      [1913 Webster]

            That we act our temporal affairs with a desire no
            greater than our necessity.           --Jer. Taylor.
      [1913 Webster]

            Industry doth beget by producing good habits, and
            facility of acting things expedient for us to do.
                                                  --Barrow.
      [1913 Webster]

            Uplifted hands that at convenient times
            Could act extortion and the worst of crimes.
                                                  --Cowper.
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   3. To perform, as an actor; to represent dramatically on the
      stage.
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   4. To assume the office or character of; to play; to
      personate; as, to act the hero.
      [1913 Webster]

   5. To feign or counterfeit; to simulate.
      [1913 Webster]

            With acted fear the villain thus pursued. --Dryden.
      [1913 Webster]

   To act a part, to sustain the part of one of the characters
      in a play; hence, to simulate; to dissemble.

   To act the part of, to take the character of; to fulfill
      the duties of.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Act \Act\ ([a^]kt), n. [L. actus, fr. agere to drive, do: cf. F.
   acte. See Agent.]
   1. That which is done or doing; the exercise of power, or the
      effect, of which power exerted is the cause; a
      performance; a deed.
      [1913 Webster]

            That best portion of a good man's life,
            His little, nameless, unremembered acts
            Of kindness and of love.              --Wordsworth.
      [1913 Webster] Hence, in specific uses:
      (a) The result of public deliberation; the decision or
          determination of a legislative body, council, court of
          justice, etc.; a decree, edit, law, judgment, resolve,
          award; as, an act of Parliament, or of Congress.
      (b) A formal solemn writing, expressing that something has
          been done. --Abbott.
      (c) A performance of part of a play; one of the principal
          divisions of a play or dramatic work in which a
          certain definite part of the action is completed.
      (d) A thesis maintained in public, in some English
          universities, by a candidate for a degree, or to show
          the proficiency of a student.
          [1913 Webster]

   2. A state of reality or real existence as opposed to a
      possibility or possible existence. [Obs.]
      [1913 Webster]

            The seeds of plants are not at first in act, but in
            possibility, what they afterward grow to be.
                                                  --Hooker.
      [1913 Webster]

   3. Process of doing; action. In act, in the very doing; on
      the point of (doing). "In act to shoot." --Dryden.
      [1913 Webster]

            This woman was taken . . . in the very act. --John
                                                  viii. 4.
      [1913 Webster]

   Act of attainder. (Law) See Attainder.

   Act of bankruptcy (Law), an act of a debtor which renders
      him liable to be adjudged a bankrupt.

   Act of faith. (Ch. Hist.) See Auto-da-F['e].

   Act of God (Law), an inevitable accident; such
      extraordinary interruption of the usual course of events
      as is not to be looked for in advance, and against which
      ordinary prudence could not guard.

   Act of grace, an expression often used to designate an act
      declaring pardon or amnesty to numerous offenders, as at
      the beginning of a new reign.

   Act of indemnity, a statute passed for the protection of
      those who have committed some illegal act subjecting them
      to penalties. --Abbott.

   Act in pais, a thing done out of court (anciently, in the
      country), and not a matter of record.
      [1913 Webster]

   Syn: See Action.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Act \Act\, v. i.
   1. To exert power; to produce an effect; as, the stomach acts
      upon food.
      [1913 Webster]

   2. To perform actions; to fulfill functions; to put forth
      energy; to move, as opposed to remaining at rest; to carry
      into effect a determination of the will.
      [1913 Webster]

            He hangs between, in doubt to act or rest. --Pope.
      [1913 Webster]

   3. To behave or conduct, as in morals, private duties, or
      public offices; to bear or deport one's self; as, we know
      not why he has acted so.
      [1913 Webster]

   4. To perform on the stage; to represent a character.
      [1913 Webster]

            To show the world how Garrick did not act. --Cowper.
      [1913 Webster]

   To act as or To act for, to do the work of; to serve as.


   To act on, to regulate one's conduct according to.

   To act up to, to equal in action; to fulfill in practice;
      as, he has acted up to his engagement or his advantages.
      [1913 Webster]

WordNet (r) 3.0 (2006):

act
    n 1: a legal document codifying the result of deliberations of a
         committee or society or legislative body [syn: act,
         enactment]
    2: something that people do or cause to happen [syn: act,
       deed, human action, human activity]
    3: a subdivision of a play or opera or ballet
    4: a short theatrical performance that is part of a longer
       program; "he did his act three times every evening"; "she had
       a catchy little routine"; "it was one of the best numbers he
       ever did" [syn: act, routine, number, turn, bit]
    5: a manifestation of insincerity; "he put on quite an act for
       her benefit"
    v 1: perform an action, or work out or perform (an action);
         "think before you act"; "We must move quickly"; "The
         governor should act on the new energy bill"; "The nanny
         acted quickly by grabbing the toddler and covering him with
         a wet towel" [syn: act, move] [ant: forbear,
         refrain]
    2: behave in a certain manner; show a certain behavior; conduct
       or comport oneself; "You should act like an adult"; "Don't
       behave like a fool"; "What makes her do this way?"; "The dog
       acts ferocious, but he is really afraid of people" [syn:
       act, behave, do]
    3: play a role or part; "Gielgud played Hamlet"; "She wants to
       act Lady Macbeth, but she is too young for the role"; "She
       played the servant to her husband's master" [syn: act,
       play, represent]
    4: discharge one's duties; "She acts as the chair"; "In what
       capacity are you acting?"
    5: pretend to have certain qualities or state of mind; "He acted
       the idiot"; "She plays deaf when the news are bad" [syn:
       act, play, act as]
    6: be suitable for theatrical performance; "This scene acts
       well"
    7: have an effect or outcome; often the one desired or expected;
       "The voting process doesn't work as well as people thought";
       "How does your idea work in practice?"; "This method doesn't
       work"; "The breaks of my new car act quickly"; "The medicine
       works only if you take it with a lot of water" [syn: work,
       act]
    8: be engaged in an activity, often for no particular purpose
       other than pleasure
    9: behave unnaturally or affectedly; "She's just acting" [syn:
       dissemble, pretend, act]
    10: perform on a stage or theater; "She acts in this play"; "He
        acted in `Julius Caesar'"; "I played in `A Christmas Carol'"
        [syn: act, play, roleplay, playact]

Moby Thesaurus II by Grady Ward, 1.0:

281 Moby Thesaurus words for "act":
   accomplish, accomplished fact, accomplishment, achieve,
   achievement, acquit, act, act a part, act as, act as foil, act out,
   acta, acting, action, actions, activism, activity, acts, address,
   adventure, affect, affectation, afterpiece, air, ape, appear,
   assume, barnstorm, be effective, be in action, be productive, bear,
   bearing, behave, behavior, behavior pattern, behavioral norm,
   behavioral science, bill, bit, blow, bluff, bring about,
   bring into being, bring to fruition, bylaw, canon, carriage, carry,
   cause, characterize, chaser, come out, comport, comportment,
   concurrent resolution, conduct, constitution, copy, counterfeit,
   coup, course, cover up, culture pattern, curtain, curtain call,
   curtain raiser, custom, dealings, decree, deed, demean, demeanor,
   deport, deportment, dictate, dictation, discourse, dissemble,
   dissimulate, divertimento, divertissement, do, doing, doings,
   edict, effectuate, effort, emote, emotionalize, employment, enact,
   enaction, enactment, endeavor, engineer, enterprise, epilogue,
   execute, exercise, exode, exodus, exploit, expository scene,
   fait accompli, fake, feat, feign, finale, folkway, form, formality,
   formula, formulary, four-flush, function, functioning, gammon,
   gest, gestures, get top billing, go, go on, goings-on, guise, hand,
   handiwork, have effect, have free play, have play, hoke act,
   impersonate, industrialize, institution, interlude, intermezzo,
   intermission, introduction, job, joint resolution, jus, law,
   lawmaking, legislation, legislature, let on, let on like, lex,
   maintien, make, make a pretense, make as if, make believe,
   make like, maneuver, manner, manners, masquerade, masquerade as,
   mass-produce, measure, method, methodology, methods, mien,
   militate, mime, mimic, misbehave, modus vivendi, motion, motions,
   move, movements, moves, number, observable behavior, occupation,
   officiate, operate, operation, operations, ordinance, ordonnance,
   overproduce, overt act, pantomime, pass for, passage, passing,
   patter, pattern, percolate, perform, performance, perk, personate,
   play, play a part, play possum, play the lead, playact, poise,
   port, portray, pose, pose as, posture, practice, praxis, prescript,
   prescription, presence, pretend, pretend to be, procedure, proceed,
   proceeding, process, produce, production, profess, prologue,
   put on, quit, react, realize, register, regulation, represent,
   res gestae, resolution, routine, rubric, rule, ruling, run, scene,
   serve, sham, shtick, simulate, sketch, skit, social science,
   song and dance, stand-up comedy act, standing order, star, statute,
   steal the show, step, stooge, striptease, stroke, stunt, style,
   swing, tactics, take, take effect, take off, thing, thing done,
   tick, tone, tour de force, transaction, tread the boards, troupe,
   turn, undertaking, upstage, volume-produce, way, way of life, ways,
   work, working, workings, works



V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

ACT
       Application Compatibility Toolkit (MS, Windows, Vista)


V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

ACT
       Architecture Characterization Template (DISA)


The Free On-line Dictionary of Computing (30 December 2018):

ACT

   1.  Annual Change Traffic.

   2.  Ada Core Technologies.


Bouvier's Law Dictionary, Revised 6th Ed (1856):

ACT, civil law, contracts. A writing which states in a legal form that a
thing has been said, done, or agreed. In Latin, Instrumentum. Merl. Rep.



Bouvier's Law Dictionary, Revised 6th Ed (1856):

ACT. In the legal sense, this word may be used to signify the result of a
public deliberation, the decision of a prince, of a legislative body, of a
council, court of justice, or a magistrate. Also, a decree, edict, law,
judgment, resolve, award, determination. Also, an instrument in writing to
verify facts, as act of assembly, act of congress, act of parliament, act
and deed. See Webster's Dict. Acts are civil or criminal, lawful or
unlawful, public or private.
    2. Public acts, usually denominated authentic, are those which have a
public authority, and which have been made before public officers, are
authorized by a public seal, have been made public by the authority of a
magistrate, or which have been extracted and been properly authenticated
from public records.
    3. Acts under private signature are those which have been made by
private individuals, under their hands. An act of this kind does not acquire
the force of an authentic act, by being registered in the office of a
notary. 5 N. S. 693; 8 N. S. 568 ; 3 L. R. 419 ; 8 N. S. 396 ; 11 M. R. 243;
unless it has been properly acknowledged before the officer, by the parties
to it. 5 N. S. 196.
     4. Private acts are those made by private persons, as registers in
relation to their receipts and expenditures, schedules, acquittances, and
the like.  Nov. 73, c. 2 ; Code, lib. 7, tit. 32, 1. 6; lib. 4, t. 21; Dig.
lib. 22, tit.. 4; Civ. Code of Louis. art. 2231 to 2254; Toull. Dr. Civ.
Francais, tom. 8, p. 94.



Bouvier's Law Dictionary, Revised 6th Ed (1856):

ACT, legislation.  A statute or law made by a legislative body; as an act of
congress is a law by the congress of the United States; an act of assembly
is a law made by a legislative assembly.  If an act of assembly expire or be
repealed while a proceeding under it is in fieri or pending, the proceeding
becomes abortive; as a prosecution for an offence, 7 Wheat. 552; or a
proceeding under insolvent laws. 1 Bl. R. 451; Burr. 1456 ; 6 Cranch, 208 ;
9 Serg. & Rawle, 283.
     2. Acts are general or special; public or private. A general or public
act is a universal rule which binds the whole community; of which the courts
are bound to take notice ex officio.
     3. Explanatory acts should not be enlarged by equity Blood's case,
Comb. 410; although such acts may be allowed to have a retrospective
operation. Dupin, Notions de Droit, 145. 9.
     4. Private or special acts are rather exceptions, than rules; being
those which operate only upon particular persons and private concerns; of
these the courts are not bound to take notice, unless they are pleaded. Com.
85, 6; 1 Bouv. Inst. n. 105.



Bouvier's Law Dictionary, Revised 6th Ed (1856):

ACT, evidence. The act of one of several conspirators, performed in
pursuance of the common design, is evidence against all of them. An overt
act of treason must be proved by two witnesses. See Overt.
     2. The terra. acts, includes written correspondence, and other papers
relative to the design of the parties, but whether it includes unpublished
writings upon abstract questions, though of a kindred nature, has been
doubted, Foster's Rep. 198 ; 2 Stark. R. 116, 141.
     3. In cases of partnership it is a rule that the act or declaration of
either partner, in furtherance of the common object of the association, is
the act of all. 1 Pet. R. 371 5 B. & Ald. 267.
     4. And the acts. of an agent, in pursuance of his authority, will be
binding on his principal. Greenl. Ev. Sec. 113.