[ bron-tuh-sawr ]
/ ˈbrɒn təˌsɔr /


a huge sauropod dinosaur of the genus Apatosaurus (formerly Brontosaurus) and closely related genera, of the Jurassic Period, having a massive body, a small head and long neck, and thick columnar limbs, and ranging up to 77 feet (23.5 meters) in length.

Origin of brontosaur

see origin at brontosaurus Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for brontosaur

  • He is a brontosaur: nine bones and six hundred barrels of plaster of Paris.

    What Is Man? And Other Stories|Mark Twain (Samuel Clemens)
  • The twenty-ton Brontosaur had a brain no larger than that of a new-born human infant.

  • The Brontosaur, though only sixty feet long, probably weighed twenty tons.

  • He is a Brontosaur: nine bones and six hundred barrels of plaster of paris.

Science definitions for brontosaur

[ brŏn′tə-sôrəs ]
brontosaur (brŏntə-sôr′)

An earlier name for apatosaurus.

Word History

Take a little deception, add a little excitement, stir them with a century-long mistake, and you have the mystery of the brontosaurus. Specifically, you have the mystery of its name. For 100 years this 70-foot-long, 30-ton vegetarian giant had two names. This case of double identity began in 1877, when bones of a large dinosaur were discovered. The creature was dubbed apatosaurus, a name that meant “deceptive lizard” or “unreal lizard.” Two years later, bones of a larger dinosaur were found, and in all the excitement, scientists named it brontosaurus or “thunder lizard.” This name stuck until scientists decided it was all a mistake-the two sets of bones actually belonged to the same type of dinosaur. Since it is a rule in taxonomy that the first name given to a newly discovered organism is the one that must be used, scientists have had to use the term apatosaurus. But “thunder lizard” had found a lot of popular appeal, and many people still prefer to call the beast brontosaurus.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.