mas·​to·​don ˈma-stə-ˌdän How to pronounce mastodon (audio)
: any of various extinct mammals (genus Mammut synonym Mastodon) of the elephant family existing from the Miocene through the Pleistocene that are distinguished from the related mammoths chiefly by molar teeth with cone-shaped cusps
: one that is unusually large
mastodonic adjective
mastodont adjective or noun

Example Sentences

mom-and-pop stores just can't compete with these mastodons of retailing
Recent Examples on the Web More than 180 other species, including mastodons, didn't Researchers think the Thylacosmilus was a hypercarnivore — an animal with a diet that was about 75% meat — similar to lions. Ashley Strickland, CNN, 21 Mar. 2023 Elsewhere in Florida, researchers are studying a sinkhole in the Aucilla River, south of Tallahassee, that served as a prehistoric watering hole for humans, mastodons, bison, bears and dogs. Sean Kingsley, Smithsonian Magazine, 29 Mar. 2023 Grand Rapids Public Museum (GRPM) will be receiving the mastodon, and shared images of volunteers and experts excavating the bones from the ground on Friday. Jason Duaine Hahn, Peoplemag, 15 Aug. 2022 The Gray Fossil mastodon. Jeanne Timmons, Ars Technica, 22 Dec. 2021 In fact, the state fossil is a mastodon. USA Today, 24 June 2021 Hard to believe an osotogari move is going to keep a 350-pound mastodon from slamming your glass body’s head on the turf. San Diego Union-Tribune, 25 Feb. 2023 Although animal bones, including those of a mastodon, were found nearby, the team concluded that the print was made by a human foot walking on saturated soil. Gemma Tarlach, Discover Magazine, 29 Apr. 2019 The tooth is believed to be from a mastodon about 11,000 to 12,000 years old. Layla Mcmurtrie, USA TODAY, 17 Aug. 2022 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'mastodon.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


borrowed from New Latin Mastodont-, Mastodon, genus name, Latinization of French mastodonte, vernacular name for the animal, from Greek mastós "breast, nipple" (probably from a pre-Greek substratal language) + French -odonte -odont; so named from the nipple-like cusps on the crowns of the molar teeth

First Known Use

1811, in the meaning defined at sense 1

Time Traveler
The first known use of mastodon was in 1811

Dictionary Entries Near mastodon

Cite this Entry

“Mastodon.” Dictionary, Merriam-Webster, Accessed 31 May. 2023.

Kids Definition


: any of various huge extinct mammals related to the mammoths and existing elephants

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