Day-Glo is a brand of fluorescent pigments and colors that are used to create bright, vibrant colors. The term is derived from the brand name, which is a combination of 'DAY' and 'GLOW'. The colors are often used in signs, posters, and other forms of advertising. The crossword solution for the term DAY-Glo is 'NEON', which is a type of gas that is used to create bright, glowing colors when it is exposed to an electrical current. NEON is often used in signs and advertisements, and is one of the most common elements used to create DAY-Glo colors.