Even in the age of smartphones, a good watch can be an essential part of your wardrobe. But with all the types of watches out there and all the strange terminology that accompanies them, it's hard to know exactly what to look for when you're in the market for a timepiece. Read on for a guide to a watch's parts and their functionality—which can extend far beyond basic timekeeping.

Watch Movements: The Big Three

One of the main considerations when buying a watch is its movement: literally, what makes it tick. Here are the three types you're likely to run into.

Manual Mechanical

Now produced mostly as a luxury item, manual mechanical watches have been around since the 17th century, when watchmakers miniaturized the timekeeping technology used in clocks. Inside a manual mechanical watch, a spring that must be periodically wound by hand keeps the gears turning. Though not as precise as their electronic successors, mechanical watches are still favored by horologists (horology = the study of time) for their delicate parts and elegant craftsmanship.

Automatic Mechanical

Developed in the 1920s and standard in mechanical watches by the 1960s, automatic movement means the watch's mainspring winds itself via the natural movements of the wearer's wrist throughout the day. This eliminates the need to wind the watch by hand, improving its accuracy.

Quartz Electronic

Replacing springs and gears, a small battery keeps a quartz watch ticking. Quartz watches are the most precise and the least expensive to manufacture, leading to their dominance over the watch market since they were first mass-produced in the 1980s.

Pro Tip: Check for Swiss-made movement. The Swiss have set the standard for watchmaking since its inception and they continue to heavily regulate the label's usage.

The Parts of a Watch, Defined

While the inside of a watch can be exceptionally complicated, its exterior can be broken down into several discrete parts. Each of these contributes to the piece's aesthetic or its functionality.

Watch Face

• Case: houses the movement and protects it from the elements; comes in a variety of shapes
• Dial: the watch face, sometimes enhanced with subdials that show seconds or chronograph readouts
• Hands: the pieces that actually indicate the time; sometimes they're filled with a luminous material to make them glow in the dark
• Markers: also known as an index (plural indices), a marker is one of the numerals around the watch face; sometimes simple lines, known as stick markers, stand in for Roman or Arabic numerals
• Crystal: this covers the dial to protect against dirt and water, and is made from one of three materials: lab-grown sapphire, which is second only to a diamond in terms of its hardness; mineral, which is simply another term for glass; or acrylic, which is similar to plastic
• Bezel: the outer frame that keeps the crystal in place; can be purely decorative or functional, with diving and stopwatch versions
• Crown: a small piece on the side of the case that winds the movement and adjusts functions such as date and time; some watches include a crown protector to avoid accidental adjustments

Watch Band

• Bracelet: a band made of metal links
• Strap: a band made of leather, vegan leather, silicone, or another flexible material
• Clasp: keeps the band secured to the wrist; the most common types are buckle (or ardillon) and deployment (or deployant) clasps

Pro Tip: A screw-down crown enhances a watch's water resistance by sealing the case against moisture and water.

Materials and Their Pros and Cons

What the watch is made of doesn't only affect how the timepiece looks—it also influences how much it weighs, how long it stays looking new, and how it interacts with your skin. And each material has its own upside and drawbacks.

Stainless Steel

• Pros: highly durable, professional looking, and hypoallergenic
• Cons: often fairly expensive

Base Metal

• Pros: less-expensive alternative to stainless steel; sometimes plated in gold
• Cons: may scratch or tarnish, and more likely to cause an allergic reaction

Silicone

• Pros: withstands abuse and available in any color of the rainbow; excellent for sports and outdoor activities
• Cons: doesn't transition well from day to evening

Leather

• Pros: soft, comfortable, and suitable for a range of occasions
• Cons: may crack or fade over years of wear

Pro Tip: Many base-metal watches have a stainless steel case back, giving you a cost-effective option that's still partially hypoallergenic.

Bells and Whistles, AKA Complications

Any watch function that extends beyond basic timekeeping is known as a complication. Here's a rundown of the complications you're most likely to see on different types of watches.

Chronograph

• What it is: a stopwatch
• Look for it if: you'd like to have a stopwatch handy without pulling out your smartphone; good for coaches and runners

Multifunction Subdial

• What it is: a subdial that indicates other elements of time: the day of the week, a 24-hour clock, or Greenwich Mean Time, for example
• Look for it if: you'd like a watch with enhanced functionality and a professional-looking face

Date Display

• What it is: a window, extra hand, or subdial that indicates the date
• Look for it if: you like to time travel

Moon-Phase Indicator

• What it is: a subdial or window that shows the full, half, quarter, or new moon
• Look for it if: you'd like a watch with a little aesthetic flair

Alarm

• What it is: a built-in reminder of an event that can be set independently of the time
• Look for it if: you run late, have a busy schedule, or need an alarm when a smartphone is out of reach

Tachymeter

• What it is: an instrument for measuring speed, usually built in as a scale on the inner or outer bezel, and usually found in conjunction with a chronograph
• Look for it if: you're a pilot or race car driver; it helps gauge the rate at which a vehicle is moving

Water Resistance and What That Actually Means

Since a watch is exposed to the elements all day long, it's vulnerable to rain, snow, and humidity. A watch's water-resistance rating indicates how much moisture the timepiece can take before it's damaged. Since these ratings aren't intuitive, we've laid out the water activities each one can and can't handle.

30 Meter (3atm)

• Suitable for: everyday use (resistant to splashes and rain)
• Avoid: showering, bathing, swimming, fishing, snorkeling, diving

50 Meter (5atm)

• Suitable for: swimming, whitewater rafting, fishing
• Avoid: snorkeling, diving

100 Meter (10atm)

• Suitable for: surfing, swimming, snorkeling, sailing, watersports
• Avoid: diving

200 Meter (20atm)

• Suitable for: skin diving, surface watersports, marine-related work
• Avoid: scuba diving

Diver's 100, 200, or 300 Meter

• Suitable for: scuba diving
• Avoid: saturation diving

Diver's 300+ Meter

• Suitable for: saturation diving
• Avoid: bragging about all the cool stuff you can do with your watch

Photo ("The Parts of a Watch, Defined"): Michelle Klosinski, Groupon