Grampus griseus vs dolphin

Grampus griseus and dolphin both are nouns.

Word	Noun	Adjective	Verb	Adverb
Grampus griseus	Yes	No	No	No
dolphin	Yes	No	No	No

As nouns, dolphin is a hypernym of Grampus griseus; that is, dolphin is a word with a broader meaning than Grampus griseus:

Grampus griseus: slaty-grey blunt-nosed dolphin common in northern seas
dolphin: any of various small toothed whales with a beaklike snout; larger than porpoises

Grampus griseus (noun)	dolphin (noun)
slaty-grey blunt-nosed dolphin common in northern seas	any of various small toothed whales with a beaklike snout; larger than porpoises
	large slender food and game fish widely distributed in warm seas (especially around Hawaii)