watch is a timepiece (Clock) that is made to be worn on a person. It is usually a wristwatch, worn on the wrist with a strap or bracelet. In addition to the time, modern watches often display the day, date (calendar date), month and year, and electronic watches may have many other functions.

Most inexpensive and medium-priced watches used mainly for timekeeping are electronic watches with quartz movements (quartz clock#Mechanism). Expensive, collectible watches valued more for their workmanship and aesthetic appeal than for simple timekeeping, often have purely mechanical movements and are powered by springs, even though mechanical movements are less accurate than more affordable quartz movements.

Before wristwatches became popular in the 1920s, most watches were pocket watches, which often had covers and were carried in a pocket and attached to a watch chain or watch fob. Watches evolved in the 1600s from spring powered clocks, which appeared in the 1400s.