Illustration of jellyfish
- jellyfish 1a
jellyfish
noun
jel·ly·fish
ˈje-lē-ˌfish 
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)
b
c
2
: a person lacking backbone or firmness
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
By-the-wind-sailors are related to anemones, corals, jellyfish and hydroids.
—
Adrian Rodriguez, Mercury News, 4 Apr. 2025
The ocean makes a stunning backdrop for a special dinner, as does a mesmerizing aquarium filled with live jellyfish.
—Lisa Cericola, Southern Living, 23 Mar. 2025
Monger battled jellyfish stings, exhausting winds and energy-sapping heat to finish the course which winds itself around Hawaii’s Big Island.
—Amanda Davies, CNN, 21 Mar. 2025
The water is a stunning aquamarine, crystal-clear, and free from algae or jellyfish.
—Lydia Mansel, Travel + Leisure, 19 Mar. 2025
See All Example Sentences for jellyfish
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Adrian Rodriguez, Mercury News, 4 Apr. 2025
The ocean makes a stunning backdrop for a special dinner, as does a mesmerizing aquarium filled with live jellyfish.
—Lisa Cericola, Southern Living, 23 Mar. 2025
Monger battled jellyfish stings, exhausting winds and energy-sapping heat to finish the course which winds itself around Hawaii’s Big Island.
—Amanda Davies, CNN, 21 Mar. 2025
The water is a stunning aquamarine, crystal-clear, and free from algae or jellyfish.
—Lydia Mansel, Travel + Leisure, 19 Mar. 2025
See All Example Sentences for jellyfish
Cite this Entry
“Jellyfish.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/jellyfish. Accessed 23 Apr. 2025.
Copy CitationKids Definition
jellyfish
noun
jel·ly·fish
ˈjel-ē-ˌfish
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
: 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
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