A graffiti signature, or 'TAG, ' is a unique symbol or phrase used by an artist to identify their work. The term GRAFFITI SIGNATURE can be broken down into three crossword solutions: GRAFFITI, SIGN, and TAG. GRAFFITI is a form of visual art that is created by spray-painting or writing on a public surface. SIGN is a mark or gesture used to convey information or instruction. TAG is a three-letter acronym used to identify the artist's work.