A large variety of devices have been invented to measure time. The study of these devices is called Horology. Here is a brief list of a few of the most popular:

  1. The most common devices in day-to-day life are the clock for periods less than a day and the calendar for periods longer than a day.
  2. Clocks can range from Watches, to more exotic varieties such as the Clock of the Long Now.
  3. Clocks can be driven by a variety of means, including a pendulum.
  4. There are also a variety of different calendars, for example the Lunar calendar and the Solar calendar, although the Gregorian calendar is the most commonly used.
  5. A chronometer is a timekeeper precise enough to be used as a portable time standard, usually in order to determine longitude by means of celestial navigation.
  6. The most accurate type of measuring devices for time are atomic clocks.
  7. More archaic devices include the Hourglass, the Sundial, the Tempometer and the Water clock.