Definitions for "Dimetrodon"
carnivorous dinosaur of the Permian in North America having a crest or dorsal sail
Dimetrodon was a predatory synapsid ('mammal-like reptile') genus that flourished during the Permian Period, living between 280 and 265 million years ago. It was more closely related to mammals than to true reptiles (Sauropsida), like dinosaurs, lizards and birds.