jellyfish
Americannoun
-
jellyfish,
plural
-
jellyfishes
plural
-
any of various marine coelenterates of a soft, gelatinous structure, especially one with an umbrellalike body and long, trailing tentacles; medusa.
-
Informal. a person without strong resolve or stamina; an indecisive or weak person.
noun
-
any marine medusoid coelenterate of the class Scyphozoa, having a gelatinous umbrella-shaped body with trailing tentacles
-
any other medusoid coelenterate
-
informal a weak indecisive person
Other Word Forms
Noun Inflected Forms
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.
Vocabulary lists containing jellyfish
Reef Awareness Day, List 1
Looking to grow your vocabulary? Check out this interactive, curated word list from our team of English language specialists at Vocabulary.com – one of over 17,000 lists we've built to help learners worldwide!
Marine Biology - Introductory
Interested in learning more words like this one? Our team at Vocabulary.com has got you covered! You can review flashcards, quiz yourself, practice spelling, and more – and it's all completely free to use!
Marine Biology - Middle School
Want to remember this word for good? Start your learning journey today with our library of interactive, themed word lists built by the experts at Vocabulary.com – we'll help you make the most of your study time!
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
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
As we reach peak jellyfish season in Scotland, should we see them as a sight to behold or a reason to run?
From BBC ● Jul. 28, 2026
When the sea starts to get warmer, it means a return of the jellyfish.
From BBC ● Jul. 28, 2026
Since then she developed the first-ever treatment for a jellyfish sting.
From "The Thing About Jellyfish" by Ali Benjamin
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
There are of course a great number of animals—such as jellyfishes, and other animals—without any hard parts, of which we cannot reasonably expect to find any traces whatever: there is nothing of them to preserve.
From Darwiniana : Essays — Volume 02 by Huxley, Thomas Henry
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
