ETYM as. clucge bell; akin to Dutch klok clock, bell, German glocke, Dan. klokke, Swed. klocka, Icel. klukka bell, Late Lat. clocca, cloca (whence French cloche); al perh. of Celtic origin; cf. Irish and Gael. clog bell, clock, w. cloch bell. Related to Cloak.
1. A device other than a watch for indicating or measuring time commonly by means of hands moving on a dial; broadly; any periodic system by which time is measured.
2. A registering device usually with a dial; specifically; odometer.
3. Time clock.
A timepiece that shows the time of day.
The device that generates periodic signals for synchronization.
Any device that measures the passage of time, usually shown by means of pointers moving over a dial or by a digital display. Traditionally a timepiece consists of a train of wheels driven by a spring or weight controlled by a balance wheel or pendulum. The watch is a portable clock.
History.
In ancient Egypt the time during the day was measured by a shadow clock, a primitive form of sundial, and at night the water clock was used. Up to the late 16th century the only clock available for use at sea was the sand clock, of which the most familiar form is the hourglass. During the Middle Ages various types of sundial were widely used, and portable sundials were in use from the 16th to the 18th century. Watches were invented in the 16th century—the first were made in Nuremberg, Germany, shortly after 1500—but it was not until the 19th century that they became cheap enough to be widely available. The first known public clock was set up in Milan, Italy, in 1353. The timekeeping of both clocks and watches was revolutionized in the 17th century by the application of pendulums to clocks and of balance springs to watches. types of clock The marine chronometer is a precision timepiece of special design, used at sea for giving Greenwich mean time (gmt). Electric timepieces were made possible by the discovery early in the 19th century of the magnetic effects of electric currents. One of the earliest and most satisfactory methods of electrical control of a clock was invented by Matthaeus Hipp in 1842. In one kind of electric clock, the place of the pendulum or spring-controlled balance wheel is taken by a small synchronous electric motor, which counts up the alternations (frequency) of the incoming electric supply and, by a suitable train of wheels, records the time by means of hands on a dial.
The quartz crystal clock (made possible by the piezoelectric effect of certain crystals) has great precision, with a short-term variation in accuracy of about one-thousandth of a second per day. More accurate still is the atomic clock. This utilizes the natural resonance of certain atoms (for example, cesium) as a regulator controlling the frequency of a quartz crystal oscillator. It is accurate to within one-millionth of a second per day.

An ornamental figure on the ankle or side of a stocking or sock.

1. The electronic circuit in a computer that generates a steady stream of timing pulses—the digital signals that synchronize every operation. The system clock signal is precisely set by a quartz crystal, typically at a specific frequency between 1 and 50 megahertz. The clock rate of a computer is one of the prime determinants of its overall processing speed, and it can go as high as the other components of the computer allow. Also called: system clock.
2. The battery-backed circuit that keeps track of the time and date in a computer—not the same as the system clock. Also called: clock/calendar.

To measure the time or duration of an event or action or the person who performs an action in a certain period of time; SYN. time.