Graffiti is writing and pictures put on walls, trains, bridges, and other public surfaces — sometimes rude, sometimes funny, sometimes political, and sometimes careful art.

Graffitigraffiti（塗鴉）is writing and pictures put on walls, trains, bridges, and other public surfaces是畫或寫在牆上、火車上、橋上，還有其他公共場所表面的文字和圖畫——sometimes rude, sometimes funny, sometimes political, and sometimes careful art有時候粗魯、有時候好笑、有時候政治意味濃厚，有時候則是用心的藝術創作。

Cities may treat it as damage; other people treat famous pieces as street art. Both views are in real use, and the tidy dictionary line (“rude writing on walls”) is tidier than the argument on the street.

Cities may treat it as damage城市可能把它當成破壞；other people treat famous pieces as street art也有人把有名的作品當成街頭藝術。Both views are in real use這兩種看法都是真實存在的，and the tidy dictionary line ("rude writing on walls")而字典裡工整的一句話（「牆上粗魯的文字」），is tidier than the argument on the street遠比街頭上的爭論來得整齊。

In English, graffiti is almost always a mass of stuff, not one countable mark: there was graffiti on the wall, a piece of graffiti. The old Italian word was a plural (one graffito, many graffiti), but English mostly stopped counting that way.

In English在英文裡，graffiti is almost always a mass of stuff, not one countable markgraffiti 幾乎都是當作不可數的一整片東西，而不是一個一個可以數的痕跡：there was graffiti on the wall, a piece of graffititthere was graffiti on the wall（牆上有塗鴉），a piece of graffiti（一處塗鴉）。The old Italian word was a plural (one graffito, many graffiti)這個字原本的義大利文是複數形式（單數是 graffito，複數是 graffiti），but English mostly stopped counting that way但英文大部分已經不這樣區分了。

People also use it as a verb: to graffiti a wall.

People also use it as a verb大家也把它當動詞用：to graffiti a wallto graffiti a wall（在牆上塗鴉）。