I. ˈchäk noun
Etymology: origin unknown
Date: 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
II. adverb
Date: 1834
: as close or as completely as possible
III. transitive verb
Date: circa 1841
: to stop or make fast with or as if with chocks