stitch vs sewing

stitch and sewing both are nouns.

Word	Noun	Adjective	Verb	Adverb
stitch	Yes	No	Yes	No
sewing	Yes	No	No	No

As nouns, sewing is a hypernym of stitch; that is, sewing is a word with a broader meaning than stitch:

stitch: a link or loop or knot made by an implement in knitting, crocheting, embroidery, or sewing
sewing: needlework on which you are working with needle and thread

Other hypernyms of stitch include stitchery.

stitch (noun)	sewing (noun)
a link or loop or knot made by an implement in knitting, crocheting, embroidery, or sewing	joining or attaching by stitches
a sharp spasm of pain in the side resulting from running	needlework on which you are working with needle and thread

stitch (verb)	sewing (verb)
fasten by sewing; do needlework