Ursus horribilis vs grizzly bear

Ursus horribilis and grizzly bear both are nouns.

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

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

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

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

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