Mat

• abstract: In the picture framing industry, a mat (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.

以上来源于: WordNet