A clock is an instrument for measuring time. There are two major types of clocks, analog and digital. Analog clocks may be mechanical or have a quartz movement.

Digital clocks use electronic methods of keeping time. Modern Quartz timepieces were invented in the 1920s and the digital clock was invented in 1956.

The clock is one of the oldest human inventions. The earliest reasonably accurate clocks are the 13th century tower clocks. The next major development in accuracy occurred in 1657 with the invention of the pendulum clock. You should have a collectible clock or decorative wall clock in your home.