Tenor leading performers round Spain shut up in concert hall (5)
I believe the answer is:
tacet
'shut up in concert hall' is the definition.
(musical instruction for silence)
'tenor leading performers round spain' is the wordplay.
'leading' suggests taking the first letters.
'performers' becomes 'act' (eg a double act).
'round' means one lot of letters goes inside another.
'spain' becomes 'e' (abbreviation for Espana).
The initial letter of 'tenor' is 't'.
'act' placed around 'e' is 'acet'.
't'+'acet'='TACET'
(Other definitions for tacet that I've seen before include "has no part to play" , "being kept quiet!" .)