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mastodon

American  
[mas-tuh-don] / ˈmæs təˌdɒn /

noun

  1. a massive, elephantlike mammal of the genus Mammut (Mastodon ), that flourished worldwide from the Miocene through the Pleistocene epochs and, in North America, into recent times, having long, curved upper tusks and, in the male, short lower tusks.

  2. a person of immense size, power, influence, etc.

mastodon British  
/ ˈmæstəˌdɒn /

noun

  1. any extinct elephant-like proboscidean mammal of the genus Mammut (or Mastodon ), common in Pliocene times

"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
mastodon Scientific  
/ măs′tə-dŏn′ /

  1. Any of several extinct mammals of the genus Mastodon (or Mammut). Mastodons resembled elephants and mammoths except that their molar teeth had conelike cusps rather than parallel ridges for grinding. Like elephants, mastodons had a pair of long, curved tusks growing from their upper jaw, but males also sometimes had a second pair from the lower jaw. Like mammoths, mastodons were covered with hair. They lived from the Oligocene Epoch to the end of the Ice Age.

Other Word Forms

  • mastodonic adjective
  • mastodontic adjective

Etymology

Origin of mastodon

1805–15; < New Latin < Greek mast ( ós ) breast + odṓn tooth

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Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Researchers in Costa Rica have unearthed fossils from a mastodon and a giant sloth that lived as many as 40,000 years ago, officials announced Friday, calling it the biggest such find here in decades.

From Barron's • Feb. 13, 2026

It turned out to be something far rarer, Lundberg said: a large section of tusk from a long-extinct mastodon.

From Seattle Times • Jun. 6, 2024

Wayne Thompson, the paleontology collections adviser at the Santa Cruz Museum of Natural History, recognized that the tooth belonged to an ancient mastodon, a creature that became extinct 10,000 years ago, CBS News reports.

From New York Times • Jun. 2, 2023

“I practically hit the floor. It was a mastodon tooth, right in the same area where we know mastodons lived in Santa Cruz County,” the adviser, Wayne Thompson, told San Francisco’s KRON-TV.

From Washington Times • Jun. 2, 2023

The goal was to mash as much mall merchandise as you could with Melvin, the mischievous mastodon.

From "Mr. Lemoncello's Library Olympics" by Chris Grabenstein

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.