/ Dictionary / Index J jellyfish: Meaning and Definition of Find definitions for: jel•ly•fish Pronunciation: ( jel'ē-fish"), [key] — pl. -fish, -fish•es. any of various marine coelenterates of a soft, gelatinous structure, esp. one with an umbrellalike body and long, trailing tentacles; medusa. a person without strong resolve or stamina; an indecisive or weak person. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: jellyfish (Thesaurus) jelly doughnut jelly fungus Related Content Daily Word Quiz: loathe Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language