from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Any of numerous characteristically colonial hydrozoan coelenterates having a polyp rather than a medusoid form as the dominant stage of the life cycle.
- n. The asexual polyp in the life cycle of a hydrozoan.
- adj. Of, relating to, or characteristic of a hydroid.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Any of many colonial coelenterates that exist mainly as a polyp; a hydrozoan
- adj. Of or pertaining to such creatures
from the GNU version of the Collaborative International Dictionary of English
- adj. Related to, or resembling, the hydra; of or pertaining to the Hydroidea.
from The Century Dictionary and Cyclopedia
- Like water; living in the water.
- Resembling the hydra, or an animal of the genus Hydra.
- Pertaining to the Hydroida or Hydroidea, or having their characters: as, a hydroid hydrozoan.
- n. One of the Hydroidea.
- n. A hydropolyp.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. colonial coelenterates having the polyp phase dominant
This gigantic creature grows from the small one, called a hydroid, represented in the small cut.
They were velella vellella - a hydroid similar to a jellyfish, with the common name of "By-the-wind-sailor".
Trematode ‘nurse’ can develop within itself the very unlike ‘Cercaria’, it will not appear impossible that the egg, or ciliated embryo, of a sponge, for once, under special conditions, might become a hydroid polype, or the embryo of a
The Yekta of the Crimson Sea, are as extraordinary developments of hydroid forms as the giant
It was a hydroid, a development of that strange animal-vegetable that, sometimes almost microscopic, waves in the sea depths like a cluster of flowers paralyzing its prey with the mysterious force that dwells in its blossom heads!
The smaller the piece, within certain limits, and the younger physiologically, the more nearly does it return to embryonic conditions, a fact which can be studied admirably in the hydroid Corymorpha.
Silurian age a very rich fauna has already developed, and representatives are found of all the main Invertebrate groups -- sponges, corals, hydroid colonies, five types of Echinoderms, Bryozoa,
You see the hydroid does not in the least resemble a jelly-fish.
It was a hydroid, a development of that strange animal-vegetable that, sometimes almost microscopic, waves in the sea depths like a cluster of flowers paralyzing its prey with the mysteri-ous force that dwells in its blossom heads!
 The Yekta of the Crimson Sea, are as extraordinary developments of hydroid forms as the giant Medusae, of which, of course, they are not too remote cousins.