therapsid

noun
the·​rap·​sid | \thə-ˈrap-səd \

Definition of therapsid 

: any of an order (Therapsida) of synapsid reptiles 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

Other Words from therapsid

therapsid adjective

First Known Use of therapsid

1912, in the meaning defined above

History and Etymology for therapsid

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

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Time Traveler for therapsid

The first known use of therapsid was in 1912

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Britannica.com: Encyclopedia article about therapsid

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