RhymeZone: chockstone definitions

Definitions of chockstone:

noun: A stone, ranging in size from a boulder to a pebble, which has become wedged in a vertical fissure or cleft.
noun: (climbing) A metal wedge or nut, threaded on a wire, used in rock climbing for protection by wedging it into a crack in the rock.

(Definitions from Wiktionary)