cornet vs serpent

cornet and serpent both are nouns.

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

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

cornet: a brass musical instrument with a brilliant tone; has a narrow tube and a flared bell and is played by means of valves
serpent: an obsolete bass cornet; resembles a snake

cornet (noun)	serpent (noun)
a brass musical instrument with a brilliant tone; has a narrow tube and a flared bell and is played by means of valves	limbless scaly elongate reptile; some are venomous
	an obsolete bass cornet; resembles a snake
	a firework that moves in serpentine manner when ignited