/ Dictionary / Index M moon jellyfish: Meaning and Definition of Find definitions for: moon' jel"lyfish Pronunciation: [key] a coelenterate, Aurelia aurita, inhabiting all seas, having a luminescent milky-pink or milky-orange, umbrellalike disk 3–9 in. (8–23 cm) in diameter. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. moonish moon knife Related Content Daily Word Quiz: winsome Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language