悬链线
一根绳子悬挂在两点之间所呈现的曲线。根据绳长、两端点之间的距离以及端点的位置不同，可能出现多种曲线形状。
Catenary
The curve assumed by a string that is suspended between two points. Many curves are possible, depending on the length of the string, the distance between the end points, and the location of the end points.