/ Dictionary / Index L leucon: Meaning and Definition of Find definitions for: leu•con Pronunciation: (l'kon), [key] — n. Zool. a type of sponge having a thick body wall with a highly branched canal system leading into the spongocoel. Cf. ascon, sycon. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. leucoma leucopenia Related Content Daily Word Quiz: tenacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language