jellyfish

noun

jel·​ly·​fish ˈje-lē-ˌfish How to pronounce jellyfish (audio)
1
a
: the typically free-swimming, bell-shaped, usually sexually-reproducing solitary or colonial form of a cnidarian in which the whorls of tentacles lined with nematocysts arise and hang down from the margin of the nearly transparent, gelatinous bell : medusa
especially : a large medusa characteristic of the siphonophores and scyphozoans (such as the sea nettle or box jellyfish)
2
: a person lacking backbone or firmness

Illustration of jellyfish

Illustration of jellyfish
  • jellyfish 1a

Examples of jellyfish in a Sentence

a jellyfish who was afraid to tell her boss that her latest brainstorm was just plain bad
Recent Examples on the Web Despite their name and translucent appearance, comb jellies aren’t closely related to jellyfish. Rudy Molinek, Smithsonian Magazine, 3 July 2024 Only four tentacles extend from the body to create the entire jellyfish, called a medusa, according to the study. Irene Wright, Miami Herald, 2 July 2024 And despite their name, they’re not closely related to jellyfish. Elizabeth Anne Brown, Scientific American, 27 June 2024 There’s also purple for dangerous sea life, like jellyfish, and double red when a beach is closed for any reason. Curt Anderson, Sun Sentinel, 25 June 2024 See all Example Sentences for jellyfish 

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

Word History

First Known Use

1818, in the meaning defined at sense 1a

Time Traveler
The first known use of jellyfish was in 1818

Dictionary Entries Near jellyfish

Cite this Entry

“Jellyfish.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/jellyfish. Accessed 19 Jul. 2024.

Kids Definition

jellyfish

noun
jel·​ly·​fish ˈjel-ē-ˌfish How to pronounce jellyfish (audio)
1
: any of numerous free-swimming coelenterate animals that reproduce sexually and have a jellylike, saucer-shaped, and usually nearly transparent body and tentacles with stinging cells
2
: any of various sea animals that resemble a jellyfish

Medical Definition

jellyfish

noun
jel·​ly·​fish ˈjel-ē-ˌfish How to pronounce jellyfish (audio)
: a free-swimming marine coelenterate that is the sexually reproducing form of a hydrozoan or scyphozoan and has a nearly transparent saucer-shaped body and extensible marginal tentacles studded with stinging cells

More from Merriam-Webster on jellyfish

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