serpent vs elapid

serpent and elapid both are nouns.

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

As nouns, elapid is a hyponym of serpent; that is, elapid is a word with a more specific, narrower meaning than serpent:

serpent: limbless scaly elongate reptile; some are venomous
elapid: any of numerous venomous fanged snakes of warmer parts of both hemispheres

serpent (noun)	elapid (noun)
limbless scaly elongate reptile; some are venomous	any of numerous venomous fanged snakes of warmer parts of both hemispheres
an obsolete bass cornet; resembles a snake
a firework that moves in serpentine manner when ignited