Plesiosauria

plural noun

Ple·​si·​o·​sau·​ria

ˌplēsēəˈsȯrēə

1

: a suborder of Sauropterygia comprising Mesozoic marine reptiles with dorsoventrally flattened bodies and limbs modified into paddles compare plesiosaurus

2

in some classifications : an order of Reptilia nearly coextensive with Sauropterygia

plesiosaurian

¦⸗⸗⸗¦sȯrēən

adjective or noun

plesiosauroid

-ȯˌrȯid

adjective

Word History

Etymology

New Latin, from plesi- + -sauria

The Ultimate Dictionary Awaits

Expand your vocabulary and dive deeper into language with Merriam-Webster Unabridged.

1. Expanded definitions
2. Detailed etymologies
3. Advanced search tools
4. All ad-free

Discover what makes Merriam-Webster Unabridged the essential choice for true word lovers.

Start Your Free Trial Now