What does coelenterate mean?
A coelenterate is any member of a former group of simple aquatic animals characterized by radial symmetry and a single internal body cavity that serves both digestion and circulation. The term traditionally covered jellyfish, sea anemones, corals, hydroids, and comb jellies, most of which live in the sea and capture prey with tentacles armed with specialized stinging or sticky cells. Modern biology has largely retired "coelenterate": the animals once lumped under it have been divided into separate phyla, with "cnidarian" now preferred for jellyfish and their relatives and "ctenophore" for comb jellies. The word survives in older textbooks, museum displays, and general natural-history writing, where its literal meaning — from Greek roots for "hollow intestine" — neatly describes these animals' defining feature: a body built around one central cavity. For readers encountering it today, "coelenterate" signals a classic, slightly dated vocabulary of marine zoology rather than current taxonomy.
An animal of the former phylum Coelenterata: a typically marine, radially symmetrical creature with a sac-like hollow body, tentacles, and stinging cells, including jellyfish, sea anemones, corals, and hydroids.
"Sea anemones are sessile coelenterates that wait for fish to wander within reach of their stinging tentacles."
Now largely replaced in scientific contexts by "cnidarian"; retained in older literature and general writing about marine life.
Relating to or characteristic of coelenterates.
"The reef's coelenterate inhabitants build structures visible from space."
Less common than the noun form.
Standard pluralization; used when referring to multiple individuals or members of the group.
"The exhibit displayed dozens of preserved coelenterates in glass jars."
Before biologists split them apart, jellyfish and sea anemones shared a phylum whose very name means "hollow gut" — because that's essentially all a coelenterate's body is.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of coelenterate
"Coelenterate" derives from New Latin Coelenterata, the phylum name coined by French naturalist Georges Cuvier around the turn of the nineteenth century, combining the Greek koilos ("hollow") and enteron ("intestine"). The English noun entered scientific usage during the nineteenth century as zoologists catalogued these radially symmetrical creatures. It shares its Greek roots with other anatomical terms such as "coelom" and "enteritis."
How coelenterate is actually used
The word is primarily scientific and formal, common in older zoology texts and popular nature writing but increasingly superseded by "cnidarian," since modern taxonomy restricts Coelenterata to Cnidaria and treats ctenophores separately. The adjective use (as in "coelenterate tissue") also exists but is less frequent than the noun.
Easily confused with coelenterate
"Cnidarian" refers to the modern phylum Cnidaria specifically, while "coelenterate" is the older, broader term that once grouped cnidarians together with ctenophores.