1. A small toothed whale (Delphinapterus leucas) chiefly of the Arctic Ocean, having a bulbous forehead and a white body when full-grown. Also called white whale.
a. A large white anadromous sturgeon (Huso huso) of the Black and Caspian Seas, valued for its roe. Also called beluga sturgeon, whitefish.
b. Caviar made from the roe of this fish, having large grayish grains.
[Russian belukha, white whale, and beluga, sturgeon : belyĭ, white; see bhel-1 in the Appendix of Indo-European roots + -uga, -ukha, augmentative suff.]
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.