[chock] n [origin unknown] (1769) 1: a wedge or block for steadying a body (as a cask) and holding it motionless, for filling in an unwanted space, or for blocking the movement of a wheel
2: a heavy metal casting (as on the bow or stern of a ship) with two short horn-shaped arms curving inward between which ropes or hawsers may pass for mooring or towing
[2]chock adv (1834): as close or as completely as possible [3]chock vt (1854): to stop or make fast with or as if with chocks