1. A mechanism usually incorporating a series of gears, which regulates the use of mechanical energy, as in the escapement in a weight-driven orchestrion, which regulates the running of the motor. An escapement usually includes a governor, also listed in this Glossary. 2. In a piano action, the mechanism which releases the hammer just before it hits the strings, allowing it to fall back. This prevents the hammer from blocking against the strings and dampening out the tone.

A decorative metal piece, usually adorning a keyhole or handle.

An automatic piano, usually electrically-operated, which has the pedals automatically controlled and which has limited suction-level variations. Examples include the Hupfeld Phonoliszt, the Recordo, and the Seeburg Style X. Many expression pianos have separate automatic controls for bass and treble hammer rails.