dayglo From WikiWord, the free dictionary English Contents DefinitionsRelated wordsReferences DefinitionsadjectiveLuminiscent; fluorescent; of colors, very bright. Related wordsSynonymsday-glofluorescentluminousbrightfulgorousfulgentfulgurousself-luminousexcandescentablazeglaryhyperfluorescentflaminglivefulguranthyperluminous References Wiktionary — dayglo Wikipedia — dayglo