Heard every instrument (3)
I believe the answer is:
awl
'instrument' is the definition.
(I have seen 'Pointed instrument ' mean 'awl' so perhaps 'instrument' could also mean 'awl')
'heard every' is the wordplay.
'heard' shows a homophone (sound like).
'every' becomes 'all' (similar in meaning).
'all' sounds like 'AWL'.
(Other definitions for awl that I've seen before include "Hide sticker" , "Pointed tool for punching holes" , "Hole-boring tool" , "Hole-piercing tool" , "has its use at last" .)