a spike (= a piece of metal with a sharp point at one end) that climbers put in cracks in the rock to support them or to attach a rope to

The climbers follow the cracks in the face where they can wedge their pitons. 登山者沿着岩壁的裂缝攀登，可以在缝中楔入岩钉。

The cables are attached to the rock face by metal pitons. 登山缆通过金属岩钉固定在岩壁上。