Bridge fit
How a frame sits on the nose: the width of its bridge and whether it rests at the right height.
Also: bridge width, low bridge fit
The bridge is the part of a frame that crosses the nose. Its width, the middle number on the arm, usually 14 to 24 millimetres, must suit the nose bridge, and its shape must let the lenses sit in front of the eyes, not on the cheeks. For low or flat nose bridges, common among many peoples of Asia and Africa, makers offer low-bridge or "alternative fit" frames with taller pads. A good bridge fit stops slipping.