'pelycosaur' definitions:

Definition of 'pelycosaur'

(from WordNet)
noun
Large primitive reptile having a tall spinal sail; of the Permian or late Paleozoic in Europe and North America

Definition of 'pelycosaur'

From: GCIDE
  • pelycosaur \pelycosaur\ n.
  • 1. A large primitive reptile having a tall spinal sail; of the Permian or late Paleozoic in Europe and North America. [WordNet 1.5]