Source : Webster's Revised Unabridged Dictionary (1913)

Kettledrum \Ket"tle*drum`\ (-dr[u^]m`), n.
   1. (Mus.) A drum made of thin copper in the form of a
      hemispherical kettle, with parchment stretched over the
      mouth of it.

   Note: Kettledrums, in pairs, were formerly used in martial
         music for cavalry, but are now chiefly confined to
         orchestras, where they are called {tympani}.

Source : WordNet®

kettledrum
     n : a large hemispherical brass or copper percussion instrument
         with a drumhead that can be tuned by adjusting the
         tension on it [syn: {kettle}, {tympanum}, {tympani}, {timpani}]