plural noun
The·​rap·​si·​da | \ -sədə\

Definition of Therapsida

: an order of synapsid reptiles that flourished during the Permian and Triassic periods with the last forms becoming extinct during the Cretaceous

Note: Reptiles of the order Therapsida are considered ancestors of the mammals.

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History and Etymology for Therapsida

New Latin, from Greek theraps attendant + New Latin -ida

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