A  | B  | C  | D  | E  | F  | G  | H  | I  | J  | K  | L  | M  | N  | O  | P  | Q  | R  | S  | T  | U  | V  | W  | X  | Y  | Z

A

Anchor
Definition: A part of an escapement of the same name. It looks like an upside-down anchor.

Arbor
Definition: The name given to mechanical shafts in horology.

B

Balance
Definition: Looks like a wheel and provides the mass for escapements which do not depend on pendulums.

Balance spring
Definition: A spiral spring, one end of which is fixed to the balance and the other end to the frame, which with the balance forms an oscillator.

Barrel
Definition: The case in which the mainspring is contained.

Beat
Definition: The even tick-tock of a clock or watch.

Bezel
Definition: A frame holding glass in front of the watch or clock face.

Brocot escapement
Definition: A type of deadbeat escapement using semi-cylindrical pins.

Bush
Definition: An annular insertion of brass into the plate to provide a fresh bearing surface for a pivot.

C

Cannon pinion
Definition: The pinion, having a long extension, which fits on the centre arbor and holds the minute hand.

Case screws
Definition: The screws which hold the movement in the case.

Centre seconds
Definition: Having a second hand concentric with the hour and minute hands.

Centre wheel
Definition: The wheel on the centre arbor.

Chiming
Definition: Producing a musical sequence of notes, often at the quarter hours.

Chronograph
Definition: A clock or watch which records intervals of time. The hands can be stopped or started at will without stopping the mechanism and interfering with the timekeeping.

Chronometer
Definition: A very accurate timekeeper.

Click
Definition: A sprung detent which stops a ratchet wheel from turning backwards.

Cock
Definition: A small plate holding one or two pivots only.

Countwheel striking
Definition: An early and simple method of controlling the number of strokes sounded at the hour.

Crown wheel
Definition: A wheel where the teeth face along the arbor and used in the verge escapement.

Cylinder escapement
Definition: A balance wheel escapement driven by the escape wheel engaging in a cutaway cylinder.

D

Deatbeat
Definition: A type of escapement without recoil.

Dial
Definition: The plate on which the numerals are marked.

E

Escapement
Definition: The device which controls the speed of the clock or watch time train.

F

Fly
Definition: The rotating flat plate or governor which controls the speed of the striking or chiming trains.

Full plate
Definition: Where the back plate covers the whole of the watch movement.

Fusee
Definition: A tapered pulley device which evens out the pull of the mainspring.

G

Going train
Definition: The train of wheels and pinions driving the escapement.

Gut line
Definition: A line used to connect weights to the movement or to connect the mainspring to the fusee. Can be made from natural gut or can be artificial.

H

Hairspring
Definition: See Balance Spring

Half plate
Definition: Where the back plate of the watch covers only about half of the movement. Separate small plates called Cocks hold the escapement and fourth wheel pivots.

Hole
Definition: A circular hole in the plate in which a pivot runs.

I

Impulse
Definition: The small push given to the balance or pendulum once or twice each oscillation.

J

Jewel
Definition: A precious or artificial stone used as a pivot hole or as an end cap for a pivot.

K

Keywind
Definition: Wound by a key.

L

Lever escapement
Definition: An escapement where an anchor shaped lever provides the impulse to the balance.

M

Mainspring
Definition: A spiral spring, usually in a barrel, used as the motive force of a clock or watch.

Motion work
Definition: The wheels and pinions linking the minute and hour hands together.

Movement
Definition: The 'works' of a clock or watch.

N

No definitions.

O

Olive
Definition: A small plunger in a watch case used in conjunction with the winding button to allow the hands to be set.

P

Pallet
Definition: The teeth, usually only two, that engage in the escape wheel.

Pendulum
Definition: A mass on the end of a rod which when acted upon by gravity provides the constant period oscillator for clocks.

Perpetual calendar
Definition: An automatic calendar in a watch or clock which takes account of the varying lengths of months and of leap years.

Pin pallet
Definition: A type of lever escapement using pins on the lever to obtain impulse.

Pinions
Definition: A name for small gears, usually made of steel, driven by the larger wheels.

Pivot
Definition: A fine extension of an arbor, running in a pivot hole.

Plate
Definition: The back or front sheet of metal of a watch or clock movement in which the pivots run.

Platform Escapement
Definition: A self-contained and removable balance escapement.

Q

No definitions.

R

Rack striking
Definition: A mechanism which superseded countwheel striking to control the number of strokes sounded at the hour. Allowed the use of repeater work.

Ratchet wheel
Definition: A toothed wheel used in conjunction with a click to allow rotation in one direction only.

Rating nut
Definition: The nut above or below a pendulum used to alter its length and so the rate at which the clock goes.

Regulation
Definition: The process of changing the rate of a clock or watch.

Regulator
Definition: The lever or other device used principally with balance escapements to alter the rate.

Repeater
Definition: A clock or watch which can strike the last hour, with in some cases, the quarter and even the minutes at will.

Run
Definition: Usually uncontrolled running of a movement

S

Split seconds
Definition: Having two second hands, each of which can be stopped at will.

Spring lug
Definition: The telescopic bar on a watch used to hold the strap.

Stemwind
Definition: A watch wound by a knob or button, not with a key.

Stop work
Definition: A mechanism connected to the winding to prevent overwinding.

Stopwatch
Definition: A watch whose mechanism can be stopped or started at will. Used for timing events. See chronograph.

Striking
Definition: Sounding the hours and perhaps the half-hours as well.

Striking train
Definition: The train of wheels and pinions controlling the striking

Suspension
Definition: A fine strip of steel, or sometimes silk thread, on which the pendulum hangs.

T

Three-quarter plate
Definition: Where the back plate of a watch covers 3/4 of the movement, with the escapement pivoted in separate cocks.

U

No definitions.

V

Verge
Definition: An early type of escapement where a crown wheel drives steel flags on the balance or pendulum arbor.

Visible escapement
Definition: An escapement mounted on the dial of a clock. Often a Brocot escapement.

W

Waterproof
Definition: A vague term. See the notes on water resistant watches.

Wheels
Definition: The larger gears that drive pinions in movements.

Winding button
Definition: The knob on a watch case that is used for winding.

Winding square
Definition: The squared end of the mainspring arbor on which the key is fitted.

Winding stem
Definition: The small shaft in the movement on which the winding button is fixed.

X

No definitions.

Y

No definitions.

Z

No definitions.