When discussing watches, there is some very specific terminology to be aware of. There are explicit names for the different parts of the watch. Taking the time to learn basic watch anatomy not only gives you a greater appreciation of what goes into constructing a timepiece but it can also help you when shopping for a watch since you will have a better understanding of the variations and details available.
The watch bezel is the ring placed on top of the case to clamp the crystal down. Bezels can range from decorative ones to functional ones marked with numeral scales. Popular bezel scales include 24-hour, 60-minute, and tachymeter scales. Bezels can also rotate and there are bidirectional turning bezels and unidirectional rotating bezels.
The watch bracelet or band is the strap attached to the case that allows the wearer to wrap the timepiece securely around the wrist. Watch bracelets are made of metal (and to a lesser degree, ceramic) while watch bands (also known as straps) can be made from a variety of softer materials such as leather, rubber or fabric.
The watch case is the main component of a timepiece that serves to house the dial, movement, bezel, crown, and lugs. Watch cases come in a countless variety of shapes, sizes, and metals, and without it, there simply is no watch.
The watch caseback is the part that comes in contact with the wrist when the watch is worn and is on the opposite side of the dial. Casebacks can vary in design and common ones include snap-on casebacks, screw-down casebacks, solid casebacks, and transparent exhibition casebacks.
The watch clasp serves to fasten both ends of the bracelet together around the wrist. Clasps come in a variety of styles from simple tang buckles (sometimes called pin buckles) to intricate folding deployant clasps for extra security.
The crown, or more correctly, the winding crown, is the knob positioned on the exterior of the case to control the movement inside the watch. The winding crown serves to wind the movement and set the time (and other functions). It is sometimes falsely called a “dial” by those not familiar with watches, which as you will see, means something completely different in watch-speak
The watch crystal is the transparent shield that sits above the dial to protect it from moisture, dust, and other elements. Vintage watches typically have acrylic (also known as Plexiglass) crystals while most modern luxury watches have scratch-resistant sapphire crystals. Some watches also have a crystal on the caseback for a view of the movement inside.
The watch dial, also commonly referred to as the “face of the watch”, is the part that houses the watch hands and any other indicators. Watch dial designs can vary dramatically and are available in an assortment of colors and materials.
Watch gaskets are rubber rings often used around the caseback, crystal, winding crown, and pushers to create airtight seals. These seals prevent water and dust from entering into the movement and are vital components to making water-resistant watches. Gaskets should be replaced every so often to maintain a timepiece’s water resistance.
The watch hands are the pointers that indicate the time and in some cases, other functions. The majority of watches have at least an hour hand and a minute hand, and most also have a seconds hand. Other common types of hands include 24-hour hands (to indicate another time zone), chronograph hands (to measure elapsed time), a power reserve hand (to indicate how much power the movement has before it will need to be wound), and calendar hands (to indicate date, day, month, year). Watch hands can be coated with luminous material to glow in the dark.
The watch hour markers (sometimes referred to as indexes or indices) are emblems on the dial to indicate the hours. Hour markers come in a variety of styles such as Arabic numerals, Roman numerals, batons, sticks, circular, triangular, and so on. Hour markers can be coated with luminous material to glow in the dark.
The watch lugs are the four pieces protruding from the case, which serve to attach the bracelet/band to the case.
Watch luminescence (sometimes referred to as lume) is the luminous material used on the watch so that parts of it glow in the dark. Watches once used radium and tritium for luminescence, which are radioluminescent materials that emit a visible light but are radioactive. Modern watches depend on non-radioactive photoluminescent substances for luminescence, which require a “charge” by exposing them to light first and then their afterglow shines in the dark. Popular brands of photoluminescent substances used today are Luminova and SuperLuminova.
A watch magnifier lens (sometimes referred to as a date magnifier or bubble magnifier) sits above the date window (on the crystal) to enlarge the numbers for easier reading. Depending on the watch, the magnifier lens can protrude above the crystal (a famous example is the Rolex “Cyclops”) or more commonly, is placed on the underside of the crystal for a smoother finish.
The watch movement, also known as a caliber, is the mechanism that powers the watch. Watch movements generally fall into two categories: quartz movements and mechanical movements. Mechanical movements are then further divided into two categories: hand-wound (or manual-wound) mechanical movements and automatic (or self-winding) movements. Quartz movements get their power from batteries, hand-wound movements get their power from manually winding the crown, and automatic movements get their power from the natural motion of one’s wrist.
A watch pusher is a button on a case that serves to activate a specific function. Some popular ones include chronograph pushers, alarm pushers, and minute repeater pushers.
The watch subsidiary dial (sometimes referred to as subdials, registers or counters) is a specific area on the watch’s main dial to indicate a particular function. Common ones are running seconds subsidiary dials, chronograph subsidiary dials, power reserve subsidiary dials, and calendar subsidiary dials.
Watch windows (sometimes referred to as apertures) are cutouts on the dial used to reveal a specific indication. Popular ones include date windows, day windows, jumping hour windows, day/night indicator windows, and moon phase windows.