copperhead vs elapid

copperhead and elapid both are nouns.

Word	Noun	Adjective	Verb	Adverb
copperhead	Yes	No	No	No
elapid	Yes	No	No	No

As nouns, elapid is a hypernym of copperhead; that is, elapid is a word with a broader meaning than copperhead:

copperhead: venomous but sluggish reddish-brown snake of Australia
elapid: any of numerous venomous fanged snakes of warmer parts of both hemispheres

Other hypernyms of copperhead include elapid snake.

copperhead (noun)	elapid (noun)
common coppery brown pit viper of upland eastern United States	any of numerous venomous fanged snakes of warmer parts of both hemispheres
venomous but sluggish reddish-brown snake of Australia