Repeated sound from the choir (4)
'repeated sound' is the definition.
(I've seen this before)
'from the choir' is the wordplay.
'from' says the answer is hidden in the clue.
'ECHO' is hidden in the letters of 'the choir'.
(Other definitions for echo that I've seen before include "Repeating of sound", "Nymph; E (radio comms.)", "Nymph whose love Narcissus spurned", "Reflect in Czechoslovakia", "Reproduction".)