escapement

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A mechanism consisting in general of an escape wheel and an anchor, used especially in timepieces to control movement of the wheel and to provide periodic energy impulses to a pendulum or balance.
• noun A mechanism, as in a typewriter, that controls the lateral movement of the carriage.
• noun An escape.
• noun A means or way of escape.

from The Century Dictionary.

• noun In pianoforte-making, that part of the action which provides that the hammer, after striking the string, shall instantly recoil, whether or not the key is released.
• noun The act of escaping; escape.
• noun The general contrivance in a timepiece by which the pressure of the wheels (which move always in one direction) and the vibratory motion of the pendulum or balancewheel are accommodated the one to the other.

from the GNU version of the Collaborative International Dictionary of English.

• noun rare The act of escaping; escape.
• noun rare Way of escape; vent.
• noun 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.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The contrivance in a timepiece (winding wrist watch) 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.
• noun a mechanism found in devices such as a typewriter or printer which controls lateral motion of the carriage
• noun an escape or means of escape

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun mechanical device that regulates movement