sierra vs Scomberomorus sierra

sierra and Scomberomorus sierra both are nouns.

Word	Noun	Adjective	Verb	Adverb
sierra	Yes	No	No	No
Scomberomorus sierra	Yes	No	No	No

As nouns, sierra and Scomberomorus sierra are synonyms defined as:

sierra and Scomberomorus sierra: a Spanish mackerel of western North America

sierra (noun)	Scomberomorus sierra (noun)
a Spanish mackerel of western North America	a Spanish mackerel of western North America
a range of mountains (usually with jagged peaks and irregular outline)