I believe the answer is:
'sew' is the definition.
(I know that sew can be written as stitch)
This is all the clue.
(Other definitions for stitch that I've seen before include "Sharp pain in side of body caused by exercise" , "result of working with needle?" , "Sharp spasm of pain in the side" , "Piece of needlework" , "Pain in the side brought on by exercise" .)