orca vs Orcinus orca

orca and Orcinus orca both are nouns.

Word	Noun	Adjective	Verb	Adverb
orca	Yes	No	No	No
Orcinus orca	Yes	No	No	No

As nouns, orca and Orcinus orca are synonyms defined as:

orca and Orcinus orca: predatory black-and-white toothed whale with large dorsal fin; common in cold seas

Other synonyms of orca include grampus, killer, killer whale, sea wolf.

orca (noun)	Orcinus orca (noun)
predatory black-and-white toothed whale with large dorsal fin; common in cold seas	predatory black-and-white toothed whale with large dorsal fin; common in cold seas