[1] : 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
see also:
agent act of attainder attainder act of bankruptcy act of faith auto-da-f'e 
act of god act of grace act of indemnity act in pais action 

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

act in pais. an act performed out of court, and not a matter of record.
pais, in law french, signifies country. a deed or an assurance transacted
between two or more private persons in the country is matter in pais. 2 bl.
com. 294.

Act >> A Words
Act, definition of term: Act
act_pag1.html

Act Up >> A Words
Act Up, definition of term: Act Up
act+up_pag1.html

Act Out >> A Words
Act Out, definition of term: Act Out
act+out_pag1.html

Act On >> A Words
Act On, definition of term: Act On
act+on_pag1.html

Act Of God >> A Words
Act Of God, definition of term: Act Of God
act+of+god_pag1.html