[AS. loc or loce.] A well-known instrument for fastening doors, drawers, chests, etc., generally opened by a key. The chief parts of a lock are the bolt or part which locks, and the staple into which the bolt enters when turned by the key. Good locks are distinguished by the number of impediments that can be interposed betwixt the key and the bolt, these impediments being called the wards of the lock, which are so arranged as to slip into corresponding grooves of the key. The tumbler-lock has two notches on the upper side of the bolt, on which rests the tumbler, which is pressed by a spring into the notches according as the lock is open or shut.