pel·​y·​co·​saur ˈpe-li-kə-ˌsȯr How to pronounce pelycosaur (audio)
: any of an order (Pelycosauria) of extinct, primitive, synapsid vertebrates (such as dimetrodon) chiefly of the Permian period often having extreme development of the dorsal vertebral processes and giving rise to the therapsids

Word History


ultimately from Greek pelyc-, pelyx bowl + sauros lizard

First Known Use

1884, in the meaning defined above

Time Traveler
The first known use of pelycosaur was in 1884

Dictionary Entries Near pelycosaur

Cite this Entry

“Pelycosaur.” Dictionary, Merriam-Webster, Accessed 18 Jun. 2024.

More from Merriam-Webster on pelycosaur

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!