mamba vs elapid snake

mamba and elapid snake both are nouns.

Word	Noun	Adjective	Verb	Adverb
mamba	Yes	No	No	No
elapid snake	Yes	No	No	No

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

mamba: arboreal snake of central and southern Africa whose bite is often fatal
elapid snake: any of numerous venomous fanged snakes of warmer parts of both hemispheres

Other hypernyms of mamba include elapid.

mamba (noun)	elapid snake (noun)
arboreal snake of central and southern Africa whose bite is often fatal	any of numerous venomous fanged snakes of warmer parts of both hemispheres