hooded seal vs true seal

hooded seal and true seal both are nouns.

Word	Noun	Adjective	Verb	Adverb
hooded seal	Yes	No	No	No
true seal	Yes	No	No	No

As nouns, true seal is a hypernym of hooded seal; that is, true seal is a word with a broader meaning than hooded seal:

hooded seal: medium-sized blackish-grey seal with large inflatable sac on the head; of Arctic and northern Atlantic waters
true seal: any of several seals lacking external ear flaps and having a stiff hairlike coat with hind limbs reduced to swimming flippers

Other hypernyms of hooded seal include earless seal, hair seal.

hooded seal (noun)	true seal (noun)
medium-sized blackish-grey seal with large inflatable sac on the head; of Arctic and northern Atlantic waters	any of several seals lacking external ear flaps and having a stiff hairlike coat with hind limbs reduced to swimming flippers