The escapement is the part of a watch’s movement that converts the linear flow of energy originating from the barrel into a back-and-forth direction. This is what causes the tick-tock motion of a timepiece, most plainly demonstrated by the pendulum of a grandfather’s clock. A traditional escapement consists primarily of an escape wheel, a pallet fork (also called an anchor) with pallet stones (also called rubies), a balance wheel, and a balance spring.
The escape wheel and pallet fork are designed to enable the balance wheel and balance spring to oscillate, so when power flows from the going train to the escape wheel, the anchor rocks back and forth, causing the balance wheel to move in a forward-backwards motion and allowing the balance spring to pulsate. With every oscillation, the escape wheel advances by one tooth, thus ensuring that the energy is released in fixed amounts every single time and enabling the movement to keep accurate time. The escapement is, therefore, the single most crucial entity in the movement because it is essentially what allows a movement to give time.
There are a number of different escapement designs conceived since the miniaturisation of timepieces from bell towers to grandfather’s clocks to table clocks, pocket watches and later on, wrist watches. Some examples include the détente escapement, the verge escapement, the cylinder escapement, and the most common Swiss anchor escapement.
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