A framework usually consisting of two sides pieces connected by bars or crosspieces, called rungs, forming steps at suitable distances.

梯子。

Figuratively, any means by which one climbs or ascends.

进身的阶段；立身成名的方法(步骤)。

Any means of rising or climbing, as a flaw in a stocking.

任何梯状物(如袜子的裂缝)。