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
Meanwhile, early versions of mollusks and sponges populated the seafloor as jellyfish floated above.
—
Marlowe Starling, Quanta Magazine, 1 May 2026
SeaWorld San Diego will host a nighttime spectacular with 600 aerial drones this summer that will light up the sky over Mission Bay with towering images of breaching whales, pulsating jellyfish and flipping dolphins.
—Brady MacDonald, Oc Register, 1 May 2026
The jellyfish-like creatures began washing up on Central Coast beaches in mid-April, The Tribune previously reported.
—Stephanie Zappelli, Sacbee.com, 23 Apr. 2026
SeaWorld likens the experience to the LED room in its Jewels of the Sea attraction that brings to life various shapes and sizes of jellyfish.
—Lori Weisberg, San Diego Union-Tribune, 23 Apr. 2026
See All Example Sentences for jellyfish
Examples are automatically compiled from online sources to
show current usage.
Read More
Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
Send us feedback.
Marlowe Starling, Quanta Magazine, 1 May 2026
SeaWorld San Diego will host a nighttime spectacular with 600 aerial drones this summer that will light up the sky over Mission Bay with towering images of breaching whales, pulsating jellyfish and flipping dolphins.
—Brady MacDonald, Oc Register, 1 May 2026
The jellyfish-like creatures began washing up on Central Coast beaches in mid-April, The Tribune previously reported.
—Stephanie Zappelli, Sacbee.com, 23 Apr. 2026
SeaWorld likens the experience to the LED room in its Jewels of the Sea attraction that brings to life various shapes and sizes of jellyfish.
—Lori Weisberg, San Diego Union-Tribune, 23 Apr. 2026
See All Example Sentences for jellyfish
Cite this Entry
“Jellyfish.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/jellyfish. Accessed 3 May. 2026.
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
Love words? Need even more definitions?
Merriam-Webster unabridged
