Rapid series of notes (9)
I believe the answer is:
glissando
'rapid series of notes' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for glissando that I've seen before include "Slide between two notes" , "note series rapidly executed" , "Note with sliding pitch" , "Effect produced by playing a series of notes very rapidly" , "Sliding series of notes (mus.)" .)