Clock face

A clock face or dial is the part of an analog clock (or watch) that displays the time through the use of a fixed-numbered dial or dials and moving hands. In its most basic form, recognized throughout the world, the periphery of the dial is numbered 1 through 12 indicating the hours in a 12-hour cycle, and a short hour hand makes two revolutions in a day. A longer minute hand makes one revolution every hour. The face may also include a second hand which makes one revolution per minute. The term is less commonly used for the time display on digital clocks and watches.

A second type of clock face is the 24-hour analog dial, widely used in military and other organizations that use 24-hour time. This is similar to the 12-hour dial above, except it has hours numbered 1–24 around the outside, and the hour hand makes only one revolution per day. Some special-purpose clocks, such as timers and sporting event clocks, are designed for measuring periods less than one hour. Clocks can indicate the hour with Roman numerals or Hindu–Arabic numerals, or with non-numeric indicator marks. The two numbering systems have also been used in combination, with the prior indicating the hour and the later the minute. Longcase clocks (grandfather clocks) typically use Roman numerals for the hours. Clocks using only Arabic numerals first began to appear in the mid-18th century.