Graffiti - images, pictures or inscriptions scratched, written or drawn in ink or paint on the walls and other surfaces. By the graffiti include any form of street painting walls, where you can find everything from simple written words to exquisite drawings.
In historical science, the term was used long ago, but in a narrower sense. When it comes to ancient epigraphic monuments, and then share the notion of "graffiti" and "dipinti." If the latter denotes the inscriptions are painted "graffiti" - scratched inscription (the term itself comes from the Italian verb graffiare - «scratch").
At present, widely used spray-art, ie painting graffiti with spray paint.