| a large, square-snouted whale, Physeter catodon, valued for its oil and spermaceti: now reduced in number and rare in some areas. |

| sperm whale 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. |
"Use ... Sperma Cete ana with redd Wyne when ye wax old." [Sir George Ripley, "The Compound of Alchemy," 1471]