Anatomy · Lesson 1 of 10
The Outside of a Watch
Case, crystal, dial, bezel, crown, lugs — learn every part of a watch you can point to.
Every hobby has its vocabulary, and watches are no exception. The good news: a watch only has about a dozen parts you can point to, and once you know their names, every review, forum post, and product page suddenly makes sense.
Use the explorer below to get familiar with each part. Don't worry about memorizing everything — the crown, bezel, lugs, and crystal are the four you'll hear about constantly.
Case
The metal housing that protects the movement. Usually steel, but also titanium, gold, bronze, or ceramic. Case diameter (e.g. 38mm, 40mm) is the number you'll see quoted most when watches are described.
The parts people actually talk about
The crown is your interface to the watch: winding, setting the time, changing the date. The bezel is the ring around the glass — decorative on a dress watch, functional on a diver or GMT. The lugs determine which straps fit (lug width, e.g. 20mm) and how large the watch wears (lug-to-lug distance). The crystal is the glass itself — sapphire on most modern watches.
One part you can't see: the caseback
Flip a watch over and you'll find the caseback — either solid metal (often engraved) or a window of sapphire called an exhibition caseback that shows off the movement inside. On the next lesson we'll go through that window and look at what's actually ticking in there.
Sizing cheat sheet
- Case diameter — the quoted size. 36–40mm is classically proportioned; 40–44mm wears larger and sportier.
- Lug-to-lug — the true footprint on your wrist. Under ~48mm fits most wrists comfortably.
- Lug width — the strap size you need to buy. 18, 20, and 22mm are the common ones.
Knowledge check
4 quick questions to lock in what you just learned.