sperm whale

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Any of several large, toothed whales of the family Physeteridae, especially Physeter catodon or P. macrocephalus, of tropical and temperate oceans, whose massive head has a cavity containing sperm oil and spermaceti and whose long intestines often contain ambergris. Also called cachalot.

Century Dictionary and Cyclopedia

1. n. The spermaceti-whale or cachalot, Physeter (or Catodon) macrocephalus, belonging to the family Physeteridæ (which see for technical characters; see also cut of skull under Physeter). It is one of the largest of animals, exceeded in length only by the great rorqual or finner, Balænoptera sibbaldi; it has teeth in the lower jaw, but none and no baleen in the upper; and the enormous square head contains the valuable product spermaceti. This whale is also the source of the best whale-oil, and its chase is a very important industry in the warmer waters of all seas. See cachalot.

Wiktionary

1. n. A whale (Physeter macrocephalus), the largest of the toothed whales.

GNU Webster's 1913

1. n. (Zoöl.) See in the Vocabulary.
2. (Zoöl.) A very large toothed whale (Physeter macrocephalus), having a head of enormous size. The upper jaw is destitute of teeth. In the upper part of the head, above the skull, there is a large cavity, or case, filled with oil and spermaceti. This whale sometimes grows to the length of more than eighty feet. It is found in the warmer parts of all the oceans. Called also cachalot, and spermaceti whale.

WordNet 3.0

1. n. large whale with a large cavity in the head containing spermaceti and oil; also a source of ambergris