1. a small vascular growth on the surface of a mucous membrane • Syn: polypus • Hypernyms: growth • Hyponyms: adenomatous polyp, sessile polyp, pedunculated polyp 2. one of two forms that coelenterates take (e.g. a hydra or coral): usually sedentary with a hollow cylindrical body usually with a ring of tentacles around the mouth - in some species of coelenterate, polyps are a phase in the life cycle that alternates with a medusoid phase • Hypernyms: coelenterate, cnidarian • Member Holonyms: Cnidaria, phylum Cnidaria, Coelenterata, phylum Coelenterata