From The Collaborative International Dictionary of English v.0.48 :
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.
[1913 Webster] Toccatella
From WordNet (r) 3.0 (2006) :
toccata
n 1: a baroque musical composition (usually for a keyboard
instrument) with full chords and rapid elaborate runs in a
rhythmically free style