chockstone

chockstone noun mountaineering

1. a stone securely jammed in a crack. It may vary in size from a pebble to a large boulder
2. another name for chock (def. 3)

Examples from the Web for chockstone Historical Examples of chockstone

With immense labour I found a chockstone above my head, and managed to force my foot free.

Prester John

John Buchan

Chockstone: a northern word for a stone wedged between the sides of a gully.

Climbing in The British Isles. Vol. 1 – England

W. P. Haskett Smith