Orcinus orca vs killer whale

Orcinus orca and killer whale both are nouns.

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

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

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

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

Orcinus orca (noun)	killer whale (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