/ Dictionary / Index D Day-Glo: Meaning and Definition of Find definitions for: Day-Glo Pronunciation: (dā'glō"), [key] — Trademark. Trademark. a brand of pigments and other products that exhibit fluorescence in daylight. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. dayfly dayglow Related Content Daily Word Quiz: clairvoyant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language