Source : Webster's Revised Unabridged Dictionary (1913)

Vacuum \Vac"u*um\, n.; pl. E. {Vacuums}, L. {Vacua}. [L., fr.
   vacuus empty. See {Vacuous}.]
   1. (Physics) A space entirely devoid of matter (called also,
      by way of distinction, absolute vacuum); hence, in a more
      general sense, a space, as the interior of a closed
      vessel, which has been exhausted to a high or the highest
      degree by an air pump or other artificial means; as, water
      boils at a reduced temperature in a vacuum.

Source : WordNet®

vacuum
     n 1: the absence of matter [syn: {vacuity}]
     2: an empty area or space; "the huge desert voids"; "the
        emptiness of outer space"; "without their support he'll be
        ruling in a vacuum" [syn: {void}, {vacancy}, {emptiness}]
     3: a region empty of matter [syn: {vacuity}]
     4: an electrical home appliance that cleans by suction [syn: {vacuum
        cleaner}]
     [also: {vacua} (pl)]

vacuum
     v : clean with a vacuum cleaner; "vacuum the carpets" [syn: {vacuum-clean},
          {hoover}]
     [also: {vacua} (pl)]

vacua
     See {vacuum}