chock / chäk/ • n. 1. a wedge or block placed against a wheel or rounded object, to prevent it from moving. ∎ a support on which a rounded structure, such as a cask or the hull of a boat, may be placed to keep it steady. 2. a fitting with a gap at the top, through which a rope or line is run. • v. [tr.] (often be chocked) prevent the forward movement of (a wheel or vehicle) with a chock. ∎ support (a boat, cask, etc.) on chocks.