Semi-rimless
Frames with a rim only along the top of the lenses, the lower edge held by a thin nylon cord.
Also: half-rim, supra
Semi-rimless, or half-rim, frames have a metal or plastic bar along the top of each lens, with a fine nylon thread in a groove around the lower edge holding the lens in place. They give a light look with some definition at the brow. A related style is the browline, where the upper rim is a heavy plastic bar. Opticians say the top line can balance a narrow forehead.