Ventilation is when you let fresh air into a place, or air a room out.

If you've ever been in a stuffy, hot room and said, "Someone open a window!" you know what it meas to need ventilation. Ventilation airs out an indoor space by letting fresh air in and stale or smelly air out, and it's more effective if you open several windows on opposite sides of the house or building. A fan in the window can also aid ventilation. The root word is the Latin ventulus, "a breeze," which comes from ventus, "wind."

Definitions of ventilation
  1. noun
    the act of supplying fresh air and getting rid of foul air
    synonyms: airing
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    type of:
    the act of improving something
  2. noun
    a mechanical system in a building that provides fresh air
    “she was continually adjusting the ventilation
    synonyms: ventilating system, ventilation system
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    type of:
    mechanical system
    a system of elements that interact on mechanical principles
  3. noun
    the bodily process of inhalation and exhalation; the process of taking in oxygen from inhaled air and releasing carbon dioxide by exhalation
    synonyms: breathing, external respiration, respiration
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    artificial respiration
    an emergency procedure whereby breathing is maintained artificially
    abdominal breathing
    breathing in which most of the respiratory effort is done by the abdominal muscles
    eupnea, eupnoea
    normal relaxed breathing
    energetic (deep and rapid) respiration that occurs normally after exercise or abnormally with fever or various disorders
    slow or shallow breathing
    an increased depth and rate of breathing greater than demanded by the body needs; can cause dizziness and tingling of the fingers and toes and chest pain if continued
    heaving, panting
    breathing heavily (as after exertion)
    Cheyne-Stokes respiration, periodic breathing
    abnormal respiration in which periods of shallow and deep breathing alternate
    smoke, smoking
    the act of smoking tobacco or other substances
    snore, snoring, stertor
    the act of snoring or producing a snoring sound
    sniffle, snivel, snuffle
    the act of breathing heavily through the nose (as when the nose is congested)
    breathing with a husky or whistling sound
    second wind
    the return of relatively easy breathing after initial exhaustion during continuous exertion
    blowing tobacco smoke out into the air
    type of:
    activity, bodily function, bodily process, body process
    an organic process that takes place in the body
  4. noun
    free and open discussion of (or debate on) some question of public interest
    synonyms: public discussion
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    type of:
    discussion, give-and-take, word
    an exchange of views on some topic
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