droop line

• 垂线,下降线

droop line的用法和样例：

例句

1. Draw a line perpendicular to the horizontal axis through the point.
   通过这两直线的交点做横轴的垂线。
2. We assume this curve has the property that every vertical line intersects it once at most.
   假想这条曲线具有这样的的性质，每一条垂线与其至多相交一点。