'black whale' definitions:

Small dark-colored whale of the Atlantic coast of the United States; the largest male acts as pilot or leader for the school [syn: pilot whale, black whale, common blackfish, blackfish, Globicephala melaena]

Large whale with a large cavity in the head containing spermaceti and oil; also a source of ambergris [syn: sperm whale, cachalot, black whale, Physeter catodon]