Source : Webster's Revised Unabridged Dictionary (1913)

Acetaldehyde \Ac`et*al"de*hyde\, n.
   Acetic aldehyde. See {Aldehyde}.

Source : WordNet®

acetaldehyde
     n : a colorless volatile water-soluble liquid aldehyde used
         chiefly in manufacture of acetic acid and perfumes and
         drugs [syn: {ethanal}]