plural noun Pel·y·co·sau·ria

Definition of Pelycosauria

  1. :  an order of primitive Permian reptiles (subclass Synapsida) that resemble mammals and often have extreme development of the dorsal vertebral processes — compare dimetrodon, edaphosaurus


adjective or noun

Love words? You must — there are over 200,000 words in our free online dictionary, but you are looking for one that’s only in the Merriam-Webster Unabridged Dictionary.

Join MWU now and get access to America’s largest dictionary, with:

  • 300,000 words that aren't in our free dictionary
  • Expanded definitions, etymologies, and usage notes
  • Advanced search features
  • Ad free!

Origin and Etymology of pelycosauria

New Latin, from pelyco- (from Greek pelyk-, pelyx wooden bowl) + -sauria

Seen and Heard

What made you want to look up Pelycosauria? Please tell us where you read or heard it (including the quote, if possible).


feeling or affected by lethargy

Get Word of the Day daily email!