grizzly bear vs Ursus arctos horribilis

grizzly bear and Ursus arctos horribilis both are nouns.

Word	Noun	Adjective	Verb	Adverb
grizzly bear	Yes	No	No	No
Ursus arctos horribilis	Yes	No	No	No

As nouns, grizzly bear and Ursus arctos horribilis are synonyms defined as:

grizzly bear and Ursus arctos horribilis: powerful brownish-yellow bear of the uplands of western North America

Other synonyms of grizzly bear include grizzly, silver-tip, silvertip, Ursus horribilis.

grizzly bear (noun)	Ursus arctos horribilis (noun)
powerful brownish-yellow bear of the uplands of western North America	powerful brownish-yellow bear of the uplands of western North America