man·tel·shelf / ˈmantlˌshelf/ (also man·tle·shelf) • n. a shelf above a fireplace. ∎ Climbing a projecting shelf or ledge of rock. ∎ Climbing a move for climbing on such a ledge from below by pressing down on it with the hands to raise the upper body, enabling a foot or knee to reach the ledge.• v. [intr.] Climbing perform a mantelshelf move.