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.