Dictionary.com
definitions

blue whale

noun

a migratory baleen whale, Balaenoptera musculus, mostly of oceans and seas in the Southern Hemisphere, growing to a length of 100 feet (30.5 meters) and having a furrowed, slate-blue skin mottled with lighter spots, in some seas acquiring a yellowish coating of diatoms on the underside: the largest mammal ever known, it is now endangered.

RELATED CONTENT

Blue Steel
Read more in this article about some frequently asked questions and fun facts related to our definitions.
READ MORE
Blue Waffle
Read more in this article about some frequently asked questions and fun facts related to our definitions.
READ MORE

Origin of blue whale

First recorded in 1850–55
Also called sulfur-bottom.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
British Dictionary definitions for blue whale

blue whale

noun

the largest mammal: a widely distributed bluish-grey whalebone whale, Sibbaldus (or Balaenoptera) musculus, closely related and similar to the rorquals: family BalaenopteridaeAlso called: sulphur-bottom
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012