Hydroid

from WordNet (r) 3.0 (2006)

hydroid
    n 1: colonial coelenterates having the polyp phase dominant
         [syn: {hydrozoan}, {hydroid}]

from The Collaborative International Dictionary of English v.0.48

Hydroid \Hy"droid\, a. [Hydra + -oid.] (Zool.)
   Related to, or resembling, the hydra; of or pertaining to the
   Hydroidea. -- n. One of the Hydroideas.
   [1913 Webster]