In Cnidaria, the basic sessile individual, contrasting with the mobile medusa. In the Anthozoa, the polyps are sexual but in the Medusozoa they are asexual and the medusa is the sexual stage. In hydroids, there are several kinds of polyp, such as hydranths (feeding polyps), nematophores (bearing cnidae), and dactylozooids. Polyps of hydroids typically occur in colonies. It is wrong to refer to a hydroid colony as a polyp.

Alternative form for polyp : polypoid.