Frame width
The full width of a glasses front, which should be close to the width of the face at the temples.
Also: total frame width
Frame width is measured across the front of a pair of glasses from hinge to hinge or at the widest point. Opticians aim for a frame about as wide as the face at the temples, so the arms run straight back without pressing in or standing off. Three numbers printed inside a temple arm, such as 52-18-140, give the lens width and bridge width in millimetres, and the temple length.