plural noun Syn·ap·to·sau·ria \sə̇ˌnaptəˈsȯrēə\

Definition of Synaptosauria

  1. :  a subclass of Reptilia comprising Permian and Mesozoic typically aquatic or amphibious reptiles with temporal openings high on the roof of the skull and including the orders Protorosauria and Sauropterygia



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 synaptosauria

New Latin, from Greek synaptos + New Latin -sauria

Seen and Heard

What made you want to look up Synaptosauria? 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!