echiuroid

noun

echi·​uroid ˌe-ki-ˈyu̇r-ˌȯid How to pronounce echiuroid (audio)
: any of a phylum (Echiura synonym Echiuroidea) of marine worms of uncertain taxonomic affinities that have a sensitive but nonretractile proboscis above the mouth

Word History

Etymology

shortened from the stem of New Latin Echiuroidea, former group name, from Echiurus, genus name (from Greek échis "viper" —of uncertain origin— + New Latin -urus "having a tail or rear of such a kind," borrowed from Greek -ouros, derivative of ourá "tail") + -oidea "animals of the nature of (the kind specified)" (from New Latin -oïdēs -oid entry 2 + -ea, neuter plural of -eus -eous) — more at ass entry 2

Note: The taxon Echiuroidea is used as a synonym of the now disused class name Chaetifera by the German zoologist Carl Claus (Lehrbuch der Zoologie, 2. Auflage, Marburg, 1883, p. 346), who perhaps originated it. The genus Echiurus was introduced by the French entomologist Félix Édouard Guérin-Méneville in Iconographie du Règne animal de G. Cuvier, tome 2, Planche des animaux invertébrés, planche 6 (1831), as a renaming of Lumbricus echiurus, introduced by the German naturalist Peter Simon Pallas in Miscellanea zoologica quibus novae imprimis atque obscurae animalium species describuntur (The Hague, 1766), pp. 146-51. The specific epithet echiurus would appear to refer to the chitinous bristles on the worm's posterior end, near the anus. If so, it seems possible that Pallas may have meant echinuris "with a bristled posterior" (see echino-) rather than echiuris. — For more on the etymology of Greek échis "viper" see the note at echinus.

First Known Use

circa 1889, in the meaning defined above

Time Traveler
The first known use of echiuroid was circa 1889

Browse Nearby Words

Echiurida
echiuroid
Echiuroidea
See all Nearby Words

Cite this Entry

“Echiuroid.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/echiuroid. Accessed 30 Oct. 2025.

Copy Citation

Share

Love words? Need even more definitions?

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

Popular in Grammar & Usage

See More

'Affect' vs. 'Effect'

Using Bullet Points ( • )

'A' or 'an'? What about before 'h'? An Indefinite Article Guide

The Difference Between 'i.e.' and 'e.g.'

What’s the difference between ‘cemetery’ and ‘graveyard’?
See More

Popular in Wordplay

See More

Skibidi, Mog & More: Gen Alpha Slang

13 Wonderful Words That You're Not Using (Yet)

Ten More Words from Taylor Swift Songs

Why do we 'bury the lede?'

'Za' and 9 Other Words to Help You Win at SCRABBLE
See More

Popular

See More

'Affect' vs. 'Effect'

Skibidi, Mog & More: Gen Alpha Slang

13 Wonderful Words That You're Not Using (Yet)
See More

Games & Quizzes

See All
Play Quordle: Guess all four words in a limited number of tries. Each of your guesses must be a real 5-letter word.
Quordle Can you solve 4 words at once?
Play Blossom: Solve today's spelling word game by finding as many words as you can using just 7 letters. Longer words score more points.
Blossom Pick the best words!
Play Missing Letter: a crossword with a twist. Each of the 25 puzzle words start with a different letter of the alphabet. Which letter is missing?
The Missing Letter A daily crossword with a twist
different halloween monsters in silhouette
A Monstrous Vocab Quiz Words That Go Bump in the Night
See All