A piton is a metal spike that rock climbers fix into a crack in the rock. You attach a rope or a clip to it, so the piton can hold you if you slip. Think of it as a strong nail made for stone. Older climbers used many pitons, and some routes still have old ones left in the rock. Many climbers now like gear they can take out again, because hammering pitons can hurt the rock — though on some climbs people still use them. It is a climbing word; if you do not climb, you may never need it. There is also a verb, to piton, meaning to put pitons in, but the metal piece itself is the usual meaning.

岩釘