orca vs grampus

orca and grampus both are nouns.

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

As nouns, orca and grampus are synonyms defined as:

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

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

orca (noun)	grampus (noun)
predatory black-and-white toothed whale with large dorsal fin; common in cold seas	slaty-grey blunt-nosed dolphin common in northern seas
	predatory black-and-white toothed whale with large dorsal fin; common in cold seas