dayfly vs ephemerid

dayfly and ephemerid both are nouns.

Word	Noun	Adjective	Verb	Adverb
dayfly	Yes	No	No	No
ephemerid	Yes	No	No	No

As nouns, ephemerid is a hypernym of dayfly; that is, ephemerid is a word with a broader meaning than dayfly:

dayfly: slender insect with delicate membranous wings having an aquatic larval stage and terrestrial adult stage usually lasting less than two days
ephemerid: short-lived insect

Other hypernyms of dayfly include ephemeropteran.

dayfly (noun)	ephemerid (noun)
slender insect with delicate membranous wings having an aquatic larval stage and terrestrial adult stage usually lasting less than two days	short-lived insect