panther vs Panthera onca

panther and Panthera onca both are nouns.

Word	Noun	Adjective	Verb	Adverb
panther	Yes	No	No	No
Panthera onca	Yes	No	No	No

As nouns, panther and Panthera onca are synonyms defined as:

panther and Panthera onca: a large spotted feline of tropical America similar to the leopard; in some classifications considered a member of the genus Felis

Other synonyms of panther include Felis onca, jaguar.

panther (noun)	Panthera onca (noun)
a leopard in the black color phase	a large spotted feline of tropical America similar to the leopard; in some classifications considered a member of the genus Felis
a large spotted feline of tropical America similar to the leopard; in some classifications considered a member of the genus Felis
large American feline resembling a lion