Source : Webster's Revised Unabridged Dictionary (1913)

Ventilation \Ven`ti*la"tion\, n. [L. ventilatio: cf. F.
   ventilation.]
   1. The act of ventilating, or the state of being ventilated;
      the art or process of replacing foul air by that which is
      pure, in any inclosed place, as a house, a church, a mine,
      etc.; free exposure to air.

            Insuring, for the laboring man, better ventilation.
                                                  --F. W.
                                                  Robertson.

   2. The act of refrigerating, or cooling; refrigeration; as,
      ventilation of the blood. [Obs.] --Harvey.

   3. The act of fanning, or winnowing, for the purpose of
      separating chaff and dust from the grain.

   4. The act of sifting, and bringing out to view or
      examination; free discussion; public exposure.

            The ventilation of these points diffused them to the
            knowledge of the world.               --Bp. Hall.

   5. The act of giving vent or expression. ``Ventilation of his
      thoughts.'' --Sir H. Wotton.

Source : WordNet®

ventilation
     n 1: the act of supplying fresh air and getting rid of foul air
          [syn: {airing}]
     2: a mechanical system in a building that provides fresh air;
        "she was continually adjusting the ventilation" [syn: {ventilation
        system}, {ventilating system}]
     3: free and open discussion of (or debate on) some question of
        public interest; "such a proposal deserves thorough public
        discussion" [syn: {public discussion}]
     4: the bodily process of inhalation and exhalation; the process
        of taking in oxygen from inhaled air and releasing carbon
        dioxide by exhalation [syn: {breathing}, {external
        respiration}, {respiration}]