sper·ma·ce·ti (spûr′mə-sētē, -sĕtē)
n. pl. sper·ma·ce·tis
A white waxy substance obtained chiefly from the head of the sperm whale, consisting of various esters of fatty acids and formerly used for making candles, ointments, and cosmetics.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
The American Heritage Dictionary Blog
Check out our blog, updated regularly, for new words and revised definitions, interesting images from the 5th edition, discussions of usage, and more.