A watch is a timepiece, typically worn either on the wrist or attached on a chain and carried in a pocket. wristwatches are the most common type of watch used today. watches evolved in the 17th century from spring powered clocks, which appeared in the 15th century. the first watches were strictly mechanical. as technology progressed, the mechanisms used to measure time have, in some cases, been replaced by use of quartz vibrations or electronic pulses.