The Collaborative International Dictionary of English v.0.48:

acetone \ac"e*tone\ ([a^]s"[-e]*t[=o]n), n. [See Acetic.]
   (Chem.)
   A volatile liquid (CH3.CO.CH3); pyroacetic spirit; methyl
   ketone; -- obtained by fermentation, the distillation of
   certain acetates, or by the destructive distillation of
   citric acid, starch, sugar, or gum, with quicklime. It is
   commonly used as a solvent.
   [1913 Webster +PJC]

   Note: The term was once also applied to a number of bodies of
         similar constitution, more frequently called ketones.
         See Ketone.
         [1913 Webster +PJC]

WordNet (r) 3.0 (2006):

acetone
    n 1: the simplest ketone; a highly inflammable liquid widely
         used as an organic solvent and as material for making
         plastics [syn: acetone, propanone, dimethyl ketone]