The Collaborative International Dictionary of English v.0.48:

Acetophenone \Ac`e*to*phe"none\ (-f[=e]"n[=o]n), n. [Acetic +
   phenyl + one.] (Chem.)
   A crystalline ketone, CH3.CO.C6H5, which may be obtained by
   the dry distillation of a mixture of the calcium salts of
   acetic and benzoic acids. It is used as a hypnotic under the
   name of hypnone.
   [Webster 1913 Suppl.]