passe-partout

Etymology
From.

Noun

 * 1) That by which one can pass anywhere; a safe-conduct.
 * 2) A master key.
 * 3) A light picture frame or mat of cardboard, wood, etc., usually put between the picture and the glass, and sometimes serving for several pictures.
 * 1) A light picture frame or mat of cardboard, wood, etc., usually put between the picture and the glass, and sometimes serving for several pictures.
 * 1) A light picture frame or mat of cardboard, wood, etc., usually put between the picture and the glass, and sometimes serving for several pictures.
 * 1) A light picture frame or mat of cardboard, wood, etc., usually put between the picture and the glass, and sometimes serving for several pictures.

Etymology
From.

Noun

 * 1) mat thick paper or paperboard border used to inset and center the contents of a frame

Noun

 * 1) master key
 * 2)  matte decorative border around a picture
 * 3) type of brush
 * 4)  ; two-man crosscut saw
 * 1) type of brush
 * 2)  ; two-man crosscut saw
 * 1)  ; two-man crosscut saw

Etymology
.

Noun

 * 1) skeleton key, master key
 * 2)  mat thick paper or paperboard border used to inset and center the contents of a frame