serpent vs cornet

serpent and cornet both are nouns.

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

As nouns, cornet is a hypernym of serpent; that is, cornet is a word with a broader meaning than serpent:

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

Other hypernyms of serpent include horn, trump, trumpet.

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