snap ring vs fastening

snap ring and fastening both are nouns.

Word	Noun	Adjective	Verb	Adverb
snap ring	Yes	No	No	No
fastening	Yes	No	No	No

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

snap ring: an oblong metal ring with a spring clip; used in mountaineering to attach a rope to a piton or to connect two ropes
fastening: restraint that attaches to something or holds something in place

Other hypernyms of snap ring include fastener, fixing, holdfast, hoop, ring, climbing equipment, rock-climbing equipment.

snap ring (noun)	fastening (noun)
an oblong metal ring with a spring clip; used in mountaineering to attach a rope to a piton or to connect two ropes	the act of fastening things together
	restraint that attaches to something or holds something in place