jellyfish

noun
jel·​ly·​fish | \ ˈje-lē-ˌfish How to pronounce jellyfish (audio) \

Definition of jellyfish

1a : : 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

Keep scrolling for more

Synonyms & Antonyms for jellyfish

Synonyms

doormat, namby-pamby, pushover, reed, weakling, wimp

Antonyms

stalwart

Visit the Thesaurus for More 

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

During another dive, a large jellyfish ran into my face in relatively deep depth. Georgia Frances King, Quartz, "The world’s most famous explorers on how they handle high-stress situations," 14 Aug. 2019 This is completely different from other bioluminescent ocean creatures like jellyfish and coral. Ashley Strickland, CNN, "These sharks glow bright green in the dark," 8 Aug. 2019 Now, Shaner and his team have identified five fluorescent proteins in the body of the jellyfish previously unknown to science. Eva Frederick, Science | AAAS, "This jellyfish makes glowing proteins previously unknown to science," 19 July 2019 To celebrate 20 years of jellyfish hunting and Krabby Patties, the athleisure brand teamed up with pro basketball player Kyrie Irving to specially create the Kyrie x SpongeBob SquarePants collection inspired by the show's two main characters. Kelsey Stiegman, Seventeen, "Nike Is Releasing a SpongeBob SquarePants Sneaker Collection and the Nostalgia is SO Real," 19 July 2019 However, the rash-causing, itch-inducing jellyfish larvae are not be confused with the small, parasitic crustaceans which feed on fish to survive (read: actual sea lice), according to the Divers Alert Network. Brittany Brown, baltimoresun.com, "Sea lice have been stinging at Virginia Beach. Is Ocean City next?," 13 July 2019 Rhode Island South Kingston: State officials are telling visitors to a local pond to watch out for jellyfish. USA TODAY, "‘Molly of Denali,’ saloon discourse, ashes by mail: News from around our 50 states," 10 July 2019 The South Walton Fire Department said jellyfish have been spotted in the area. Leada Gore | Lgore@al.com, al.com, "Latest beach conditions: Jellyfish in Destin, Panama City; bacteria advisory in Panama City Beach," 5 July 2019 This bizarre jellyfish shape is what most interested the authors of the study, a team of paleomagnetists led by Nikolai Østgaard of the University of Bergen in Norway. Jill Kiedaisch, Popular Mechanics, "When the Sun’s Magnetic Field Squashes the Earth’s Magnetic Field, Beautiful Things Happen," 14 Feb. 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'jellyfish.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of jellyfish

1818, in the meaning defined at sense 1a

Keep scrolling for more

Keep scrolling for more

More Definitions for jellyfish

jellyfish

noun

English Language Learners Definition of jellyfish

: a sea animal that has a very soft body and that can sting

jellyfish

noun
jel·​ly·​fish | \ ˈje-lē-ˌfish How to pronounce jellyfish (audio) \

Kids Definition of jellyfish

: a free-swimming sea animal related to the corals that has a nearly transparent jellylike body shaped like a saucer and tentacles with stinging cells

jellyfish

noun
jel·​ly·​fish | \ ˈjel-ē-ˌfish How to pronounce jellyfish (audio) \

Medical Definition of jellyfish

: 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

Keep scrolling for more