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.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.