Lock1  —n. 1 mechanism for fastening a door etc., with a bolt that requires a key of a particular shape to work it. 2 confined section of a canal or river within sluice-gates, for moving boats from one level to another. 3 a turning of a vehicle's front wheels. B (in full full lock) maximum extent of this. 4 interlocked or jammed state. 5 wrestling-hold that keeps an opponent's limb fixed. 6 (in full lock forward) player in the second row of a rugby scrum. 7 mechanism for exploding the charge of a gun. —v. 1 a fasten with a lock. B (foll. By up) shut (a house etc.) Thus. C (of a door etc.) Be lockable. 2 a (foll. By up, in, into) enclose (a person or thing) by locking. B (foll. By up) colloq. Imprison (a person). 3 (often foll. By up, away) store inaccessibly (capital locked up in land). 4 (foll. By in) hold fast (in sleep, an embrace, a struggle, etc.). 5 (usu. In passive) (of land, hills, etc.) Enclose. 6 make or become rigidly fixed. 7 (cause to) jam or catch.  lock on to (of a missile etc.) Automatically find and then track (a target). Lock out 1 keep out by locking the door. 2 (of an employer) subject (employees) to a lockout. Under lock and key locked up.  lockable adj. [old english]