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

Examples of echinoderm in a Sentence

Recent Examples on the Web In fact, most aquatic invertebrates and all echinoderms (sea stars, sea urchins, sea cucumbers, and sand dollars) start life as planktonic larvae before growing into the adult form we’re used to seeing. Jennifer Adler, Vox, 7 July 2024 The animals are the first transgenic echinoderms, the phylum that includes starfish, sea cucumbers and other marine animals. Corinne Purtill, Los Angeles Times, 29 May 2024 But these barely scratch the surface of animal diversity, with things like cephalopods, insects, and echinoderms all having distinct features. John Timmer, Ars Technica, 17 May 2023 The researchers also want to prove that the other echinoderms are covered in headlike regions as well. Lori Youmshajekian, Scientific American, 3 Nov. 2023 This group includes echinoderms like sea star and bilateral animals including vertebrates. Laura Baisas, Popular Science, 1 Nov. 2023 This contradicts textbook descriptions of echinoderms, the evolutionary group that includes starfish, as animals that have lost their head. Lori Youmshajekian, Scientific American, 3 Nov. 2023 Searching for heads and trunks Sea stars are invertebrates that belong to a group of animals called echinoderms. Laura Baisas, Popular Science, 1 Nov. 2023 The most common types of creatures in the CCZ are arthropods, worms, echinoderms (spiny invertebrates like sea urchins), and sponges. Melissa Breyer, Treehugger, 26 May 2023

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'echinoderm.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

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 14 Jul. 2024.

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

More from Merriam-Webster on echinoderm

Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!