cadenza

kadenssi puhekieltä A part of a piece of music, such as a concerto, that is very decorative and is played by a single musician.
1993, John Banville, Ghosts

Yes, laugh, as I want to laugh for instance in the concert hall when the orchestra trundles to a stop and the virtuoso at his piano, hunched like a demented vet before the bared teeth of this enormous black beast of sound, lifts up deliquescent hands and prepares to plunge into the cadenza.