LOCK

a lock is a fastening which consists of a bolt held by one or more movable parts in a certain position, and requiring a key which will manipulate hese movable parts in the required way, fore they can be moved. The most rimitive forms of fastening were by means of knotted thongs or a wooden or metal bar placed acro the inside of a door. The modern lock is the product of evolution from such a bar, sliding in R: Reis and entering a hole in the door post.