Cut short series of performances by contralto in gallery (8)
I believe the answer is:
truncate
'cut short' is the definition.
(to truncate something is to cut it short)
'series of performances by contralto in gallery' is the wordplay.
'series of performances' becomes 'run' (as in a theatrical run).
'by' is a charade indicator (letters next to each other).
'contralto' becomes 'c' (musical abbreviation).
'in' means one lot of letters goes inside another.
'gallery' becomes 'tate' (Tate Modern, Tate Britain etc).
'run'+'c'='runc'
'runc' inserted within 'tate' is 'TRUNCATE'.
(Other definitions for truncate that I've seen before include "Cut short" , "Lop" , "Dock" , "Shorten by cutting off the top" , "Make shorter by cutting off" .)