grummet vs fastener

grummet and fastener both are nouns.

Word	Noun	Adjective	Verb	Adverb
grummet	Yes	No	No	No
fastener	Yes	No	No	No

As nouns, fastener is a hypernym of grummet; that is, fastener is a word with a broader meaning than grummet:

grummet: fastener consisting of a metal ring for lining a small hole to permit the attachment of cords or lines
fastener: restraint that attaches to something or holds something in place

Other hypernyms of grummet include fastening, fixing, holdfast.

grummet (noun)	fastener (noun)
fastener consisting of a metal ring for lining a small hole to permit the attachment of cords or lines	restraint that attaches to something or holds something in place
	a person who fastens or makes fast