black whale vs Physeter catodon

black whale and Physeter catodon both are nouns.

Word	Noun	Adjective	Verb	Adverb
black whale	Yes	No	No	No
Physeter catodon	Yes	No	No	No

As nouns, black whale and Physeter catodon are synonyms defined as:

black whale and Physeter catodon: large whale with a large cavity in the head containing spermaceti and oil; also a source of ambergris

Other synonyms of black whale include cachalot, sperm whale.

black whale (noun)	Physeter catodon (noun)
large whale with a large cavity in the head containing spermaceti and oil; also a source of ambergris	large whale with a large cavity in the head containing spermaceti and oil; also a source of ambergris
small dark-colored whale of the Atlantic coast of the United States; the largest male acts as pilot or leader for the school