Mat

In the picture framing industry, a mat (or matte, or mount in British English) is a thin, flat piece of paper-based material included within a picture frame, which serves as additional decoration and to perform several other, more practical functions, such as separating the art from the glass. Putting mats in a frame is called matting, a term which can also usually be used interchangeably with mat. The French term, occasionally used in English, is passe-partout (or passepartout). A picture (a photo or print, drawing, etc.) is placed beneath it, with the cutout framing it. The passe-partout serves two purposes: first, to prevent the image from touching the glass, and second, to frame the image and enhance its visual appeal. The cutout in the passe-partout is usually beveled to avoid casting shadows on the picture. The French word may also be used for the tape used to stick the back of the picture to its frame.