cachalot

n. large toothed whale having square head with a cavity full of a mixture of sperm oil and spermaceti

The Sperm Whale (Physeter macrocephalus) is the largest of all toothed whales and is the largest toothed animal alive, measuring up to 18 metres (60 ft) long. The whale was named after the milky-white waxy substance, spermaceti, found in its head and originally mistaken for sperm. The Sperm Whale's enormous head and distinctive shape, as well as its central role in Herman Melville's Moby-Dick, have led many to describe it as the archetypal whale. Partly because of Melville, the Sperm Whale is commonly associated with the Leviathan of the Bible.
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Noun
1. large whale with a large cavity in the head containing spermaceti and oil; also a source of ambergris
(synonym) sperm whale, black whale, Physeter catodon
(hypernym) toothed whale
(member-holonym) Physeter, genus Physeter

n. sperm whale, cachalot

(n.)
The sperm whale (Physeter macrocephalus). It has in the top of its head a large cavity, containing an oily fluid, which, after death, concretes into a whitish crystalline substance called spermaceti. See Sperm whale.