Attention during rehearsals (3)
I believe the answer is:
ear
'attention' is the definition.
(having someone's ear is having their attention)
'during rehearsals' is the wordplay.
'during' indicates the answer is hidden within the clue.
'EAR' can be found hidden inside 'rehearsals'.
(Other definitions for ear that I've seen before include "Discernment musicians need" , "Organ involved with balance" , "Corn seed-holder" , "Organ inside heart" , "Lend one and listen" .)