The Collaborative International Dictionary of English v.0.48:
Cadenza \Ca*den"za\, n. [It.] (Mus.) A parenthetic flourish or flight of ornament in the course of a piece, commonly just before the final cadence. [1913 Webster]WordNet (r) 3.0 (2006):
cadenza n 1: a brilliant solo passage occurring near the end of a piece of music