Lexicon
0–9
A
B
C
- CarrouselRotating escapement cage, akin to a tourbillon, that takes its power separately
- Centre secondsA seconds hand on the central axis that travels across the whole dial
- CerachromRolex's patented ceramic bezel material, introduced in 2005 to replace aluminium
- ChronographA watch with a stopwatch built in alongside its normal timekeeping
- CompassShows the cardinal directions, by a sun-based bezel or an electronic sensor
- COSCThe Swiss body that tests watch movements and certifies them as chronometers
- Countdown timerComplication that counts down the minutes before a sailing race starts
D
- DateThe day of the month, shown in a dial window or by a pointer hand
- Dauphine handsLong, tapered watch hands shaped like a stretched triangle with facets
- DayA calendar complication that shows the day of the week, by disc or by hand
- Day-dateComplication that shows the weekday alongside the numbered day of the month
- Day/night indicatorComplication that shows whether the time shown falls in daytime or night-time hours
- Dead-beat secondsA mechanical complication that makes the seconds hand jump once each second
- Depth gaugeA watch complication that shows how far below the water's surface the wearer is
- Dive watchWatch made to be worn underwater, resisting water to a pressure above 1.1 MPa
- Double tourbillonWatch movement fitted with two tourbillons instead of one
- Dual timeShows the time in two places at once, often with an extra 24-hour hand
E
F
G
- GMTWatch complication that shows the hour in a second time zone
- GMT bezelRotating 24-hour scale, read with a 24-hour hand to show another time zone
- Grand complicationA watch combining several complications, usually timing, astronomical and striking
- Grande sonnerieStriking complication that chimes the hour and the quarters at every quarter hour
- GuillochéA fine, repeating pattern cut into a dial by a hand-worked engine-turning machine
H
I
J
L
M
- Minute repeaterChiming complication that sounds the time to the minute at the press of a button
- Monopusher chronographChronograph that starts, stops and resets with one button, usually in the crown
- MonthA calendar complication that shows the current month on the dial
- Moon phaseDial display that shows how the Moon currently looks from Earth
O
P
- Perpetual calendarA calendar mechanism that tracks month lengths and leap years without manual help
- Petite sonnerieChiming complication that strikes the hours, then only the quarters, by itself
- Pointer dateCalendar complication in which a hand points to dates printed around the dial edge
- Power reserve indicatorA complication showing how much stored energy a watch has left
- Pulsometer scaleA chronograph scale for reading a person's heart rate from a counted number of beats
Q
R
S
- Sidereal timeTime kept by the Earth's turn against the fixed stars rather than the Sun
- Sky chartWatch display of the stars turning across the sky as they appear to move
- Slide ruleRotating bezel with logarithmic scales for multiplying and dividing on the wrist
- Small secondsSeconds shown on a separate off-centre sub-dial instead of by a central hand
- Split-seconds chronographA chronograph with two seconds hands for timing two events that start together
- Sunrise and sunsetComplication showing the local times at which the Sun rises and sets
T
- Tachymeter scaleA chronograph scale that turns the time taken over a set distance into speed
- Telemeter scaleChronograph dial scale that estimates the distance to an event you can see and hear
- Tide indicatorA watch complication that shows when the next high and low tides are due
- TourbillonA turning cage for the balance and escapement, meant to help a watch keep better time
- Triple calendarA complication showing the day of the week, the date and the month
- Tropical dialVintage watch dial whose colour has changed with age, classically black to brown