Rŏck'ing-stōne, n.
n. A stone, often of great size and weight, resting upon another stone, and so exactly poised on some edge or corner, that it can be rocked, or slightly moved, with but little force.
n. A stone, often of great size and weight, resting upon another stone, and so exactly poised on some edge or corner, that it can be rocked, or slightly moved, with but little force.