grey whale vs baleen whale

grey whale and baleen whale both are nouns.

Word	Noun	Adjective	Verb	Adverb
grey whale	Yes	No	No	No
baleen whale	Yes	No	No	No

As nouns, baleen whale is a hypernym of grey whale; that is, baleen whale is a word with a broader meaning than grey whale:

grey whale: medium-sized greyish-black whale of the northern Pacific
baleen whale: whale with plates of whalebone along the upper jaw for filtering plankton from the water

Other hypernyms of grey whale include whalebone whale.

grey whale (noun)	baleen whale (noun)
medium-sized greyish-black whale of the northern Pacific	whale with plates of whalebone along the upper jaw for filtering plankton from the water