/ Dictionary / Index L leuco base: Meaning and Definition of Find definitions for: leu'co base" Pronunciation: (l'kō), [key] — Chem. Chem. a noncolored or slightly colored compound that is produced by reducing a dye and is readily oxidized to regenerate the dye. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. leuco- leucoblast Related Content Daily Word Quiz: lunar Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language