Escapement

Part of speech: noun (n.)

1. The act of escaping; escape. [R.]

2. Way of escape; vent. [R.] An escapement for youthful high spirits. G. Eliot.

3. The contrivance in a timepiece which connects the train of wheel work with the pendulum or balance, giving to the latter the impulse by which it is kept in vibration; -- so called because it allows a tooth to escape from a pallet at each vibration.