hydroid

/ˌhaɪˈdrɔɪd/

Other forms: hydroids

Definitions of hydroid

1. noun

   colonial coelenterates having the polyp phase dominant
   synonyms: hydrozoan

   types:

   planula

   the flat ciliated free-swimming larva of hydrozoan coelenterates

   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

   nanomia

   small creatures resembling pieces of fuzzy rope; each with a cluster of swimming bells serving as the head and long elastic tentacles for drawing in prey

   Portuguese man-of-war, jellyfish, man-of-war

   large siphonophore having a bladderlike float and stinging tentacles

   praya

   colonial siphonophore of up to 130 ft long

   apolemia

   large siphonophore of up to 50 ft long

   type of:

   cnidarian, coelenterate

   radially symmetrical animals having saclike bodies with only one opening and tentacles with stinging structures; they occur in polyp and medusa forms