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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.


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]


(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]
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
References in periodicals archive ?
Schmidt Consulting Hagenuk Marinekommunikation Haivision Harris Corporation Harris Corporation (Exelis) HITT Traffic Hutchinson Hydroid Hydronalix Ifokus Engineering AS Independent Robotics Inc.
Hydroid presented SEA Corporation with a plaque on October 12, recognizing its commitment to excellence in customer service and technical expertise.
The company's offering includes the Remus 600 and the smaller portable Remus 100, both from Kongsberg Hydroid.
Currently, I am studying large-scale transport of biota on marine debris along with Dale Calder (curator emeritus of Invertebrate Zoology at the ROM, and, like me, a hydroid taxonomist).
The influence of the epizoic hydroid Hydractinia angusta on the recruitment of the Antarctic scallop Adamussium colbecki.
It looks like a jellyfish but is a closely-related hydroid, and each 'animal' is in fact made up of a colony of individuals.
Kongsberg's REMUS family of AUVs built by its subsidiary Hydroid can also perform visual pipeline inspections and pipeline surveys when equipped with high-frequency sidescan sonar, a multi-beam and camera.
Chemotaxis during fertilization in the hydroid Campanularia.
The bottle brush hydroid occurs in these chalk reefs.
In January 2002, various species of algae, sponge, hydroid and tunicate colonies were scraped from the south jetty during an extremely low tide.