Terminology

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Screw eyes  
Screws with small eyelets at one end that are used to attach the hanging wire to the back of the wooden frame.

Secondary Mount  
The mount which is closer to the glass than the primary mount. While the primary mount is usually white, the secondary mount will often be a colour.

Spacer  
Material used to prevent artwork from touching the glass. It can be made of whatever is convenient, such as strips of wood, mount board, lath or any commercial product designed for this use.