This is a unit of measure for the pulse of the watch, i.e. its beat rate. In the case of a mechanical watch, it refers to how many swings/ticks the balance wheel makes in an hour. Older watches tend to have slower beat rates of 18,000 (5 ticks per second) or 21,600 vph (6 ticks per second); today’s watches typically beat at 28,800 vph, and some would be rated at 36,000 vph. Generally, the faster the beat rate, the more accurate the watch, but at the expense of greater mechanical wear and reduced power reserve.

Invented by Abraham-Louis Breguet in the 17th century, the tourbillon is a rotating cage that houses the escapement, which turns in an anti-clockwise direction to counter the effects of gravity on timing precision. While vital to the accuracy of pocket watches, tourbillons today remain a sought-after complication that tests a watchmaker’s technical prowess.

The beating heart of a mechanical watch is a spring-mounted balance wheel making several oscillations every second at a constant rate, delicately poised on a wire-thin staff. This complex assembly should be safely boxed and placed somewhere undisturbed, but is instead worn on the wrist, exposed to the full range of the wearer’s physical activities. Shock resistance refers to various systems built into the movement to protect the balance from disruptive forces and impact, to deliver consistent oscillations without breaking. 

A feature sometimes used on the displays of complication watches, a retrograde display has a start and end point, typically fanning over s scale and indicated by a hand. When the hand reaches the end point of the retrograde, it snaps back to the starting point.

An electronically powered movement that uses a battery as a power source and a synthetic quartz oscillator to regulate the timing of the watch via electrical pulses. It was invented in the late 1970s. Being far cheaper to produce and boasting greater precision than mechanical watches, quartz movements infamously almost wiped out mechanical watch production in the 1980s.

Even cleverer than the annual calendar, a perpetual calendar watch will correctly display the date for all months, and even factor for leap years. See also: Annual Calendar

A watch that chimes the time upon demand, usually by activating a pusher or slider. A minute repeater chimes the hours, quarter hours, and the minutes, using separate tones for each. It is considered to be one of the most difficult and sophisticated watches in the complication category.

In English this is often used as a verb, to refer to the act of making something. In watchmaking, it’s also a habit lifted from the French to use it as a noun, to refer to a company that manufactures watches. As opposed to many companies that assemble watches with movements sourced externally, a ‘manufacture’ is one that creates its own movements to be used in its own watches. See also: In-House.

An intricate decorative technique comprising patterns made up of tiny repetitive lines, made using an engine lathe.   

Part of the Swatch Group, ETA SA Manufacture Horlogère Suisse is the largest movement manufacturer in Switzerland, supplying an overwhelming portion of Swiss brands. Watches over a broad spread of price range could have fundamentally the same movement beating within them, with movements in higher value watches being better finished, or modified for better performance and reliability. 

The Contrôle Officiel Suisse des Chronomètres is the institute tasked with testing and certifying Swiss watches for accuracy. Those that pass, are referred to as “chronometers”. 

Refers to a feature or function in a watch, beyond telling time. Relatively simple complications include date display, moon phase; ‘higher’ complications of greater complexity include chronograph, tourbillon, perpetual calendar and minute repeater.

In terms of accuracy, it’s normal for mechanical watches to deviate between 10 to 20 seconds, out of 86,400 seconds in a day. Watches that bear the label “COSC certified chronometer” means the movement has passed COSC standard for accuracy, deviating within -4/+6 seconds a day. Digital watches generally deviate by a second a day, or less.

Watches with a stopwatch function. Besides regular chronographs, there are also flyback chronographs that allow for quick timings of successive events; and rattrapante or split seconds chronographs for recording lap times.

A mechanical watch's timekeeping precision can be affected by interference from gadgets emitting magnetic sources, such as microwave equipment or mobile phones. To counter this, some brands house their mechanical movements inside a soft iron protective layer to repel magnetic fields.