(redirected from Hydroids)
Also found in: Thesaurus, Medical, Encyclopedia, Wikipedia.


1. Any of numerous solitary or colonial hydrozoans having a polyp rather than a medusa as the dominant stage of the life cycle.
2. The asexual polyp in the life cycle of a hydrozoan.

hy′droid′ adj.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


1. (Animals) of or relating to the Hydroida, an order of colonial hydrozoan coelenterates that have the polyp phase dominant
2. (Zoology) (of coelenterate colonies or individuals) having or consisting of hydra-like polyps
(Zoology) a hydroid colony or individual
[C19: from hydra + -oid]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(ˈhaɪ drɔɪd)

1. of or pertaining to the hydrozoan order Hydroidea, including hydras and marine colonial forms.
2. the phase of hydrozoan development that consists of polyp forms.
[1860–65; hydr(a) + -oid; compare New Latin Hydroidea]
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.hydroid - colonial coelenterates having the polyp phase dominanthydroid - colonial coelenterates having the polyp phase dominant
cnidarian, coelenterate - radially symmetrical animals having saclike bodies with only one opening and tentacles with stinging structures; they occur in polyp and medusa forms
planula - the flat ciliated free-swimming larva of hydrozoan coelenterates
class Hydrozoa, Hydrozoa - coelenterates typically having alternation of generations; hydroid phase is usually colonial giving rise to the medusoid phase by budding: hydras and jellyfishes
hydra - small tubular solitary freshwater hydrozoan polyp
siphonophore - a floating or swimming oceanic colony of polyps often transparent or showily colored
sertularian - feathery colony of long-branched stems bearing stalkless paired polyps
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.
References in periodicals archive ?
hiltoni consists mostly of hydroids and other cnidarians; however, individuals of this species are known to attack and consume other sea slugs, particularly small, soft-bodied aeolids and dendronotaceans, including conspecifics (Goddard et al.
Over time, hard structures on the reefs are covered with algae, mussels, barnacles, sponges, anemones, hydroids, temperate corals, and other types of encrusting organisms.
"My advice is to never touch the wrecks since many are covered with fire sponges, hydroids, shellfish and broken edges that can cause injuries." Divers are allowed to descend a maximum of 40 meters for an hour and 15 minutes.
These psychedelic slugs, also called nudibranchs, are known to feed on tentacled marine organisms known as hydroids, which are related to corals and sea anemones.
Among hydroids, few species occur intertidally, and even fewer species tolerate air exposure (e.g., Halecium beanii, H.
Epibiont invertebrates (e.g., hydroids, polychaetes and barnacles) on decapods may also benefit from resuspended debris (Williams & Moyse, 1988) or the diet of the host (Bowers, 1968; Abello et al., 1990).
A variety of organisms attach to the shells of molluscs, including algae, protozoans, sponges, hydroids, anemones, serpulid worms, limpets, mussels, barnacles, tanaids, amphipods, tunicates, and others.
Marine stings or bites from coral, starfish, sea urchins, jellyfish, hydroids, cone shells, octopuses, puffer fish, stingrays, bony fish, weaver fish, sea snakes, lionfish, and stonefish.
We collected pycnogonids from hydroids (Family Haleciidae; 1-30 m deep) by scuba-diving in and around Friday Harbor, Washington (48[degrees] 32' N, 123[degrees] 00' W), in June, 2015.
Red king crab juveniles are strongly attracted to shallow-water, structured habitat, such as cobble, algae, and hydroids (Sundberg and Clausen (1); McMurray et al.