Definition of vacuum

What does the word vacuum mean?

• part of speech: noun

  (pl. -ums, -a). Space entirely devoid of matter, as nature abhors a v.; space, vessel, from which air has been almost exhausted by air-pump &c. (Guerickian, torriceltian, v., produced by air-pump, by mercury-pump as in mercurial barometer); (loosely) partial diminution of pressure below normal atmospheric pressure; v.-brake, continuous train-brake in which pressure is caused by exhaustion of air from bellows pulling brake-rod; v.-cleaner, apparatus for removing dust &c. by suction; v. -gauge (for testing pressure consequent on production of v.); v.-tube, sealed glass tube with almost perfect v. for observing passage of electric discharge. [Latin]

• part of speech: noun

  v. flask, with two walls separated by v. jacket, so that liquid in the inner receptacle retains its heat.