the·​rap·​sid thə-ˈrap-səd How to pronounce therapsid (audio)
: any of an order (Therapsida) of advanced synapsid vertebrates that flourished during the Permian and Triassic periods with the last forms becoming extinct during the Cretaceous period and that are considered ancestors of the mammals
therapsid adjective

Examples of therapsid in a Sentence

Recent Examples on the Web But there’s still much to learn about this terrifying therapsid, and its life before the largest extinction event in the history of the planet. Sara Kiley Watson, Popular Science, 14 Sep. 2023 Scientists have classified the four-legged predators as therapsids, along with the creatures that evolved into modern-day mammals. Matt Hrodey, Discover Magazine, 24 May 2023

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

Word History


New Latin Therapsida, from ther- mammal (from Greek thēr wild animal) + apsid-, apsis arch, vault — more at fierce, apsis

First Known Use

1912, in the meaning defined above

Time Traveler
The first known use of therapsid was in 1912

Dictionary Entries Near therapsid

Cite this Entry

“Therapsid.” Dictionary, Merriam-Webster, Accessed 13 Apr. 2024.

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