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.
  2. 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.
  3. A formal solemn writing, expressing that something has been done.
  4. 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.
  5. A thesis maintained in public, in some English universities, by a candidate for a degree, or to show the proficiency of a student.
  6. A state of reality or real existence as opposed to a possibility or possible existence.
  7. Process of doing; action. In act, in the very doing; on the point of (doing).

v. t.

  1. To move to action; to actuate; to animate.
  2. To perform; to execute; to do.
  3. To perform, as an actor; to represent dramatically on the stage.
  4. To assume the office or character of; to play; to personate; as, to act the hero.
  5. To feign or counterfeit; to simulate.

v. i.

  1. To exert power; to produce an effect; as, the stomach acts upon food.
  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.
  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.
  4. To perform on the stage; to represent a character.