zipper vs fastening

zipper and fastening both are nouns.

Word	Noun	Adjective	Verb	Adverb
zipper	Yes	No	Yes	No
fastening	Yes	No	No	No

As nouns, fastening is a hypernym of zipper; that is, fastening is a word with a broader meaning than zipper:

zipper: a fastener for locking together two toothed edges by means of a sliding tab
fastening: restraint that attaches to something or holds something in place

Other hypernyms of zipper include fastener, fixing, holdfast.

zipper (noun)	fastening (noun)
a fastener for locking together two toothed edges by means of a sliding tab	the act of fastening things together
	restraint that attaches to something or holds something in place

zipper (verb)	fastening (verb)
close with a zipper