GRAFFITO
graffito, graffiti
(noun) a rude decoration inscribed on rocks or walls
Source: WordNet® 3.1
Etymology
Noun
graffito (plural graffiti)
(archaeology and related fields) An informal inscription, as by a worker or vandal.
(rare) A single instance of graffiti in the art/vandalism sense.
Synonyms
• graffitus
Usage notes
Outside of archaeology, graffiti or “a piece of graffiti” is used for the singular. As graffiti is borrowed from a plural form, prescriptivists consider singular use of graffiti incorrect: compare data/datum. The use of "graffiti" in contemporary art is a synonym to "Tags-Throw-ups-Pieces", TTP in short.
Source: Wiktionary
Graf*fi"to, n. [It., fr. graffio a scratching.] (Art)
Definition: Production of decorative designs by scratching them through a
surface of layer plaster, glazing, etc., revealing a different-
colored ground; also, pottery or ware so decorated; -- chiefly used
attributively.
Source: Webster’s Unabridged Dictionary 1913 Edition