echi·​no·​derm i-ˈkī-nə-ˌdərm How to pronounce echinoderm (audio)
: any of a phylum (Echinodermata) of radially symmetrical coelomate marine animals including the starfishes, sea urchins, and related forms
echinodermatous adjective

Example Sentences

Recent Examples on the Web Thousands of suction cups rippled furiously against the glass as each echinoderm struggled to inch the prize toward its own maw. Quanta Magazine, 11 Jan. 2023 The footage of this pasta-looking echinoderm is actually pretty exciting because of a connection to food: Scientists got a first look at the creature eating. Rachel E. Greenspan, Time, 11 July 2019 Ernst Haeckel’s intention was to make the natural forms of elusive organisms accessible to artists, and supply them with a new visual vocabulary of protists, mollusks, trilobites, siphonophores, fungi, and echinoderms. The New York Review of Books, 16 Dec. 2018 Bertrand Lefebvre of with the French National Center for Scientific Research (CNRS) and the Laboratoire de Géologie in Lyon, France, discovered that the millennia-old mystery animal is, in fact, an echinoderm—from the same family as a starfish. David Grossman, Popular Mechanics, 22 Feb. 2019 The first saw the emergence of brachiopods and molluscs, the second that of annelids, cnidarians, echinoderms and chordates (a group that includes the vertebrates). The Economist, 7 June 2018 That is in contradistinction to Cambrian fossils, among which are found representatives of all the main animal groups (annelids, arthropods, brachiopods, chordates, cnidarians, echinoderms, molluscs and so on) that are around today. The Economist, 7 June 2018 The lure of lucrative echinoderms may have proved too strong for three Southeast fishermen. Zaz Hollander, Anchorage Daily News, 15 Mar. 2018 Feather stars are echinoderms, like the more familiar sea stars. National Geographic, 9 Dec. 2016 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'echinoderm.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Word History


borrowed from French échinoderme, borrowed from New Latin Echinoderma, taken as singular of Echinodermata, from echino- echino- + -dermata, neuter plural of -dermatos -dermatous

Note: Echinodermata was a pre-Linnaean taxon that comprised animals of the present-day class Echinoidea. The name Echinodermata, "those having hedgehog-like skin," was coined by the German jurist and naturalist Jacob Theodor Klein (1685-1759) in Naturalis dispositio Echinodermatum (Danzig, 1734).

First Known Use

1835, in the meaning defined above

Time Traveler
The first known use of echinoderm was in 1835

Dictionary Entries Near echinoderm

Cite this Entry

“Echinoderm.” Dictionary, Merriam-Webster, Accessed 28 Jan. 2023.

Kids Definition


echi·​no·​derm i-ˈkī-nə-ˌdərm How to pronounce echinoderm (audio)
: any of a phylum of marine invertebrate animals (as starfishes, sea urchins, and sea cucumbers) that have a number of similar body parts (as the arms of a starfish) arranged around a central axis, a calcium-containing inner skeleton, and a water-vascular system

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