What does dayglo mean?
Dayglo refers to a type of fluorescent pigment that emits an extraordinarily bright, saturated glow, especially under ultraviolet light, and by extension describes anything colored in those vivid neon-like shades. The word originated as a trade name — Day-Glo — created for the fluorescent paints developed in the United States in the 1930s, and it has since become a genericized term used informally for any similarly brilliant color. In everyday use, 'dayglo' functions both as a noun ('a poster painted in dayglo') and, more commonly, as an adjective modifying colors, clothing, signage, or artwork ('dayglo green', 'dayglo leggings'). The word often evokes retro aesthetics: the psychedelic concert posters of the 1960s, rave culture of the late twentieth century, or high-visibility workwear and safety equipment designed to be unmissable. Its connotations are bold, playful, and attention-grabbing rather than subtle or elegant, making it a useful shorthand for describing color at its most unrestrained.
A fluorescent pigment or paint that glows brightly under ultraviolet light and appears intensely luminous in normal light.
"She mixed the dayglo into the ink to make the flyer impossible to ignore."
Usually used attributively or in lowercase as a generic term; the capitalized form remains a trademark.
Having the strikingly bright, fluorescent quality characteristic of Day-Glo colors.
"He turned up at the party in a dayglo orange windbreaker."
Dayglo began as a brand name invented in the 1930s by two brothers experimenting in their parents' California garage — and its eye-searing pigments went on to define everything from psychedelic rock posters to safety vests.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of dayglo
Dayglo derives from Day-Glo, an American trademark coined in the 1930s for fluorescent paints developed by Robert Switzer and his brother Joseph, combining 'day' with 'glow' to suggest pigments that seem luminous even in daylight. Like many successful brand names, it gradually became genericized into the lowercase common noun and adjective used today. It shares its constituent elements with ordinary English words built on 'day' (daylight, daybreak) and 'glow' (afterglow, glowworm).
How dayglo is actually used
Informal register. Originally a trademark (Day-Glo), now widely used generically in lower case, much like 'kleenex' or 'zipper'. Often carries connotations of the 1960s–80s psychedelic aesthetic, retro design, or high-visibility safety gear.