jellyfish

American  

[jel-ee-fish] / ˈdʒɛl iˌfɪʃ /

noun

• jellyfish,
  plural
• jellyfishes
  plural

1. any of various marine coelenterates of a soft, gelatinous structure, especially one with an umbrellalike body and long, trailing tentacles; medusa.

2. Informal. a person without strong resolve or stamina; an indecisive or weak person.

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jellyfish British  

/ ˈdʒɛlɪˌfɪʃ /

noun

1. any marine medusoid coelenterate of the class Scyphozoa, having a gelatinous umbrella-shaped body with trailing tentacles

2. any other medusoid coelenterate

3. informal a weak indecisive person

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Other Word Forms

Noun Inflected Forms

• jellyfish
  plural
• jellyfishes
  plural

Etymology

Origin of jellyfish

1700–10; 1910–15 jellyfish for def. 2; jelly + fish

Explanation

A jellyfish is a marine animal with long tentacles that hang down from a bell-shaped body. Many jellyfish are nearly transparent. Jellyfish may look like they're made of jelly, but their bodies are actually 95 percent water. These umbrella-shaped creatures look graceful floating in the water, but they collapse into a flat blob on land. Jellyfish don't have organs, just a simple nervous system and three layers including the elastic, jelly-like mesoglea that gives them their name. In the 19th century, it became fairly common to call a weak person a jellyfish, a figurative usage that's still around today.

Example Sentences

See Examples For:

jellyfish jellyfishes

A collaged print by Liu Shiyuan presents a dizzying array of images—fruit, bees, jellyfish, shrouded figures, fabric samples—that is more disorienting than anything else.

From The Wall Street Journal ● Aug. 21, 2026

France on Wednesday recorded a more than 20 percent shortfall in nuclear power production capacity, a record deficit caused by environmentally related outages linked to drought, extreme heat and a jellyfish invasion.

From Barron's ● Aug. 12, 2026

C3 is an evolutionarily ancient protein found even in simple animals such as sponges and jellyfish.

From Science Daily ● Aug. 8, 2026

Especially when, after telling Max that she is going snorkeling, Sara gets left behind amid a bloom of jellyfish right out of “Finding Nemo.”

From Los Angeles Times ● Jul. 29, 2026

Aunt Sponge, fat and pulpy as a jellyfish, came waddling up behind her sister to see what was going on.

From "James and the Giant Peach" by Roald Dahl

These showed body plans different from any animals alive today, although some seem to be related to worms and jellyfishes.

From Textbooks ● Jan. 1, 2018

“We need to clearly acknowledge that jellyfishes and other gelatinous organisms may be a regular prey for a variety of marine predators.”

From National Geographic ● Sep. 15, 2017

When jellyfishes move, their tissue alternates between these states of tautness and gooeyness.

From Scientific American ● Jun. 24, 2015

Expect giraffes and zebras, but also Komodo dragons, jellyfishes and newts for a dash of originality.

From The Guardian ● Feb. 1, 2013

In animals like sea-anemones and jellyfishes the general symmetry of the body is radial; that is to say, there is no right or left, and the body might be halved along many planes.

From The Outline of Science, Vol. 1 (of 4) A Plain Story Simply Told by J. Arthur Thomson

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