Passe-Partout
The French phrase passe-partout, pronounced pas-par-too, translates literally as “passes everywhere,” meaning something is all-purpose or universal. (Passe-partout is also sometimes the term used for a master or skeleton key.) In terms of framing, it refers to a very basic framing technique in which a picture, usually with a mat, is placed behind a piece of glass and then the layers of glass, mat, picture, and backing are secured together with thin adhesive strips pasted over the edges. The adhesive strips are also occasionally referred to as passe-partout themselves.
Reference note by p4A editorial staff; August 2011