Source : Webster's Revised Unabridged Dictionary (1913)

Toccata \Toc*ca"ta\, n. [It., fr. toccare to touch. See
   {Touch}.] (Mus.)
   An old form of piece for the organ or harpsichord, somewhat
   in the free and brilliant style of the prelude, fantasia, or
   capriccio.

Source : WordNet®

toccata
     n : a baroque musical composition (usually for a keyboard
         instrument) with full chords and rapid elaborate runs in
         a rhythmically free style