Now updated for CSW19. New words, if any, and new inflections of existing words, are shown in red.
| acaleph | (Greek) a kind of jellyfish. |
| acalephae | a class of jellyfish which includes the medusae. |
| acalephan | (Of or like) an acaleph, a kind of jellyfish. |
| acalephe | (Greek) a kind of jellyfish. |
| actinia | (Lat.) a sea anemone of the genus Actinia; loosely any sea anemone. |
| actinian | a sea anemone of the genus Actinia; loosely any sea anemone. |
| actinopod | any protozoan of the phylum Actinopoda, such as a radiolarian or a heliozoan, having stiff radiating cytoplasmic projections. |
| actinozoan | belonging to the class Anthozoa of marine coelenterates. |
| aequorin | a kind of jellyfish. |
| alcyonarian | a member of the Alcyonaria, the order to which sea-pens, red coral and organ-pipe coral belong. |
| anthozoan | any animal of the class Anthozoa of marine coelenterates, which includes sea anemones, corals, and sea-pens. |
| anthozoic | of or like an anthozoan, any animal of the class Anthozoa of marine coelenterates. |
| arrowworm | a peculiar transparent worm of the genus Sagitta, living at the surface of the sea. |
| ascidian | a sea-squirt or tunicate. |
| ascon | a type of sponge. |
| asconoid | like an ascon, a type of sponge. |
| asterid | a starfish. |
| asteridian | a starfish. |
| asteroidean | an echinoderm of the class Asteroidea, comprising the starfishes. |
| aurelia | (Ital.) a jellyfish of genus Aurelia. |
| bipinnaria | the larva of certain starfishes as developed in the free-swimming stage. |
| chaetognath | a kind of marine worm. |
| chaetopod | a member of the Chaetopoda, bristle-worms. |
| chondrophore | a medusoid hydrozoan that resembles a jellyfish. |
| chondrophorine | a member of the Chondrophora, a suborder of hydrozoans similar to medusae but with a different internal structure. |
| clamworm | a marine worm. |
| cnidarian | a coelenterate, that includes sea anemones, hydra, jellyfish, and coral. |
| coelenterate | a classification of animals that includes sea anemones, hydra, jellyfish, and coral. |
| coenosteum | the calcareous skeleton of a coral colony. |
| comatula | (Lat.) a type of crinoid, aka feather star. |
| comatulid | a type of crinoid, aka feather star. |
| copperworm | the shipworm. |
| coral | a mass of marine animal skeletons. |
| coralline | a marine animal, esp a bryozoan, which lives in colonies resembling coral. |
| corallum | (Lat.) the coral or skeleton of a zoophyte. |
| cormidium | (Lat.) an aggregation of polyps in a colonial marine hydrozoan. |
| crinoid | a family of marine creatures, the sea lilies and feather stars. |
| crinoidal | of or like a crinoid, a family of marine creatures. |
| crinoidean | like a crinoid; (noun) a crinoid. |
| crossfish | another name for the common sea urchin. |
| ctenophoran | a member of the Ctenophora, transparent, free-swimming marine organisms resembling jellyfishes. |
| ctenophore | a marine animal with comblike cilia. |
| dinoflagellate | a kind of marine protozoan, one of the principal constituents of plankton. |
| discomedusan | a member of the Discomedusae, an order of jellyfishes with flattened umbrella. |
| discophoran | a jellyfish. |
| discophorous | relating to the Discophora, an order of jellyfish. |
| echinoderm | one of the Echinodermata, starfishes, sand dollars, sea urchins, and sea cucumbers. |
| echinodermal | of or like an echinoderm. |
| echinodermatous | of or like an echinoderm. |
| echinoid | an echinoderm of the class Echinoidea, a sea urchin. |
| echinus | (Lat.) a sea-urchin. |
| echiuran | one of the Echiura, a phylum of marine invertebrates, aka spoonworms. |
| gastraea | a hypothetical ancestor of the Metazoa, sponges etc. |
| gastrea | a hypothetical ancestor of the Metazoa, sponges etc. |
| globigerina | a minute marine invertebrate of the genus Globigerina, with a calcareous shell of globose chambers in a spiral. |
| gorgonian | any of various horny corals of the order Gorgonacea, with upright, plantlike forms. |
| haliplankton | plankton living in sea water. |
| hexact | six-rayed; (noun) a six-rayed creature. |
| hexactinellid | a kind of six-rayed sponge. |
| holoplankton | organisms which remain as plankton throughout their whole life cycle. |
| holothurian | any member of a class of wormlike unarmoured echinoderms, aka sea cucumbers. |
| hornwrack | a bryozoan of the genus Flustra. |
| hyalonema | a genus of sponges, aka glass-rope sponge. |
| hydra | (Lat.) a freshwater hydrozoon of the genus Hydra. |
| hydrocoral | any hydrozoan coelenterate of an order which includes the millepores. |
| hydrocoralline | relating to an order of Hydrozoa, millepores, etc; (noun) a member the Hydrozoa. |
| hydroid | related to, or resembling, a hydra; (noun) a creature related to, or resembling, the hydra. |
| hydromedusa | a hydrozoan in its medusoid stage. |
| hydromedusan | a hydromedusa. |
| hydromedusoid | a hydromedusa. |
| hydropolyp | a hydrozoan polyp. |
| hydrosoma | all the zooids of a hydroid colony collectively. |
| hydrosomal | relating to a hydrosoma, a hydroid colony. |
| hydrosomatous | of or like hydrosomata. |
| hydrosome | all the zooids of a hydroid colony collectively. |
| hydrozoan | any coelenterate of the class Hydrozoa, comprising organisms that are mostly marine and colonial with polyp and medusoid stages in the life cycle. |
| hydrozoon | any coelenterate of the class Hydrozoa, comprising organisms that are mostly marine and colonial with polyp and medusoid stages in the life cycle. |
| irukandji | a very venomous jellyfish found mainly near Australia. |
| jellyfish | a marine coelenterate with jellylike body. |
| leucon | a sponge of complex structure. |
| limulus | (Lat.) a horseshoe crab. |
| lithistid | any of the Lithistida, hard stony sponges. |
| longworm | as in sea longworm, a kind of marine worm. |
| madreporal | relating to madrepore, a kind of coral. |
| madrepore | a coral of the common reef-building type, occurring esp in tropical seas. |
| madreporian | a coral, a madrepore. |
| madreporic | relating to madrepore, a kind of coral. |
| medusa | (Lat.) a kind of jellyfish. |
| medusal | relating to a medusa, a kind of jellyfish. |
| medusan | relating to a medusa, a kind of jellyfish; (noun) a jellyfish. |
| medusiform | resembling a jellyfish. |
| medusoid | like a medusa; (noun) a sexual hydrozoan that remains attached to the parent hydroid colony. |
| meroplankton | plankton consisting of certain larvae that do not spend all their life as plankton. |
| microplankton | very small plankton. |
| millepore | any of a group or order of colonial hydrozoans. |
| monaxon | a monaxonic sponge or spicule. |
| nannoplankton | very small plankton. |
| nanoplankton | very small plankton. |
| nectocalyx | the swimming bell or umbrella of a jellyfish of medusa. |
| nematophore | a mouthless type of hydrozoan polyp. |
| neustic | of or like neuston, minute organisms floating or swimming on water's surface. |
| neuston | (Ger.) the aggregate of minute aquatic organisms that inhabit the surface of a body of water. |
| neustonic | of or like neuston, minute organisms floating or swimming on water's surface. |
| noctiluca | (Lat.) a roughly spherical marine dinoflagellate of the genus Noctiluca, which is strongly phosphorescent. |
| obelia | any of a genus of small marine colonial hydroids. |
| ophiura | a member of the Ophiura genus of brittle-stars or sand-stars. |
| ophiuran | a member of the Ophiura genus of brittle-stars or sand-stars. |
| ophiurid | a member of the Ophiura genus of brittle-stars or sand-stars. |
| ophiuroid | a member of the Ophiura genus of brittle-stars or sand-stars. |
| palolo | (Samoan) a type of seaworm, found in the Pacific. |
| parazoan | any member of the Parazoa, a sponge. |
| parazoon | any member of the Parazoa, sponges. |
| pennatula | a sea-pen. |
| pentacrinoid | a young form of some crinoids that resembles Pentacrinus. |
| peridinian | a dinoflagellate, a kind of marine protozoan. |
| peridinium | a dinoflagellate, a kind of marine protozoan. |
| phoronid | a wormlike marine animal. |
| physalia | a genus of large oceanic Siphonophora which includes the Portuguese man-of-war. |
| phytoplankton | vegetable plankton, that includes diatoms, desmids, and dinoflagellates. |
| phytoplanktonic | relating to phytoplankton. |
| plankter | an individual in plankton. |
| planktic | relating to plankton. |
| plankton | tiny, free-floating organisms of the ocean or other aquatic systems. |
| planktonic | relating to plankton. |
| planoblast | any free-swimming gonophore of a hydroid; a hydroid medusa. |
| plumularian | a member of the Plumularia, a kind of Hydrozoa. |
| pluteal | of or pertaining to a pluteus, the free-swimming larva of sea urchins and ophiurans. |
| pluteus | (Lat.) a sea-urchin or brittle-star larva. |
| pogonophoran | any of a phylum Pogonophora of marine wormlike animals. |
| polychaete | a type of aquatic worm (including lugworms and ragworms). |
| polychete | a type of aquatic worm (including lugworms and ragworms). |
| polyparium | the framework and base of a polyp colony, esp coral. |
| polypary | the framework and base of a polyp colony, esp coral. |
| polypide | a polyp of a colonial animal. |
| polypidom | a coral, or corallum; also, one of the coral-like structure made by bryozoans and hydroids. |
| polypine | of or like a (colonial) polyp. |
| polypite | a polyp of a colonial animal. |
| polyzooid | like or of the nature of a polyzoon. |
| polyzoon | one of the individual zooids forming the compound organism of a polyzoan. |
| porifer | (Lat.) a member of the Porifera, the sponges. |
| poriferal | relating to the Porifera, sponges. |
| poriferan | relating to the Porifera, sponges; (noun) a member of the sponge family. |
| pycnogonid | one of the Pycnogonida, sea-spiders. |
| pycnogonoid | of or like a pycnogonid, a sea-spider. |
| pyrosome | any of a genus of compound tunicates, with brilliant phosphorence. |
| rhabdosphere | an aggregation of rhabdoliths in oceanic ooze. |
| rhizocaul | the rootlike stalk of a hydrozoan colony. |
| sabella | (Lat.) a genus of tubicolous annelids having a circle of plumose gills around the head. |
| salp | any member of a genus of oceanic tunicates. |
| salpa | any member of a genus of oceanic tunicates. |
| salpian | any member of a genus of oceanic tunicates. |
| salpid | any member of a genus of oceanic tunicates. |
| sarcenchymatous | of or like a sarcenchyme, a soft tissue of sponges with close-packed cells and reduced gelatinous matrix. |
| sarcenchyme | a soft tissue of sponges with close-packed cells and reduced gelatinous matrix. |
| scyphozoan | any of a class of medusoid coelenterates; a jelly fish. |
| seaworm | any marine worm. |
| serpula | a member of a genus of marine annelids or tubeworms. |
| serpulid | a marine polychaete worm. |
| sertularian | a colonial hydroid with polyps arranged in pairs. |
| seston | (Ger.) a very small plankton organism. |
| siphonophore | a marine creature, colonial in habit. |
| siphonophorous | of or like a siphonophore, a type of colonial hydrozoan. |
| sipunculid | a kind of marine worm with a retractile proboscis. |
| sipunculoid | a kind of marine worm with a retractile proboscis. |
| spatangoid | a heart urchin, a member of the Spangoidea, an order of more or less heart-shaped sea urchins with eccentric anus. |
| spoonworm | a marine invertebrate of the phylum Echiura with a spoon-like mouthpiece. |
| starfish | a star-shaped marine animal. |
| stellerid | a starfish. |
| stelleridan | a starfish. |
| stomatopod | one of the Stomatopoda, marine crustaceans, including the squilla. |
| strobila | (Lat.) a stack of immature larval jellyfish formed on a scyphistoma by budding. |
| strobilar | of or like a strobila, a stack of immature larval jellyfish. |
| sunstar | a kind of starfish. |
| sycon | a type of sponge. |
| syconoid | of or like a sycon, a type of sponge. |
| tetraxon | a sponge spicule with four axes. |
| trepang | (Malay) a sea cucumber eaten as a Chinese or Japanese delicacy. |
| triaxon | a triaxial sponge spicule. |
| trochophore | a free-swimming pelagic form of many invertebrates. |
| trochosphere | a free-swimming pelagic form of many invertebrates. |
| tubularian | any hydroid belonging to the suborder Tubularida. |
| tunicate | one of a class of marine animals, including ascidians. |
| tunicated | having the form of a tunicate. |
| zoantharian | a member of the Zoantharia, the order including sea-anemones. |
| zoarial | relating to a zoarium, the zooids of a polyzoan colony. |
| zoophytic | relating to a zoophyte, a plantlike animal, as coral, sea anemone, etc. |
| zoophytical | relating to a zoophyte, a plantlike animal, as coral, sea anemone, etc. |
| zooplankter | a single zooplankton. |
| zooplankton | tiny, free-floating organisms in aquatic systems. |
| zooxanthella | a symbiotic dinoflagellate of the genus Symbiodinium that lives in the tissues of a number of marine invertebrates and protists. |