press stud vs fastening

press stud and fastening both are nouns.

Word	Noun	Adjective	Verb	Adverb
press stud	Yes	No	No	No
fastening	Yes	No	No	No

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

Other hypernyms of press stud include fastener, fixing, holdfast.

press stud (noun)	fastening (noun)
a fastener used on clothing; fastens with a snapping sound	the act of fastening things together
	restraint that attaches to something or holds something in place