/ Dictionary / Index W water flea: Meaning and Definition of Find definitions for: wa'ter flea" Pronunciation: [key] any of various small crustaceans that move about in the water like fleas, as those of the genus Daphnia. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. water flag waterflood Related Content Daily Word Quiz: crockery Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language