Dictionary
hy•dro•zo•an
Pronunciation: (hī"dru-zō'un), [key]—
n.
any freshwater or marine coelenterate of the class Hydrozoa, including free-swimming or attached types, as the hydra, in which one developmental stage, either the polyp or medusa, is absent, and colonial types, as the Portuguese man-of-war, in which both medusa and polyp stages are present in a single colony.
—
adj.
belonging or pertaining to the Hydrozoa.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.