Use a needle, so we hear (3)
I believe the answer is:
sew
'use a needle' is the definition.
(you use a needle when sewing)
'so we hear' is the wordplay.
'we hear' indicates a 'sounds like' (homophone) clue.
'so' sounds like 'SEW'.
(Other definitions for sew that I've seen before include "Do some needlework" , "Make stitches" , "Fasten with needle and thread" , "Stitch with needle and thread" , "Tack" .)