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