The hemline is how long a dress, skirt, or coat is — where the bottom edge sits on the body. If a skirt’s hemline is at the knee, the cloth stops at the knee. Fashion writers talk about hemlines rising (skirts getting shorter) or falling (getting longer), as if that edge were a line moving up or down the leg. Though actually, the hem itself is the little folded, sewn edge of the cloth; the hemline is that edge thought of as a line, or as a length. People say a mid-calf hemline or an ankle hemline when they want to be exact. You use it of clothes that hang, much more than of trousers, and never of the thread used to sew the edge. It is a fashion and sewing word, not a maths word.

裙襬；裙長、下擺的高度