Abbreviated "Hz," one Hertz is equal to one cycle per second. In 1883, Heinrich Hertz detected electromagnetic waves, and his name was adopted to measure the number of electromagnetic waves, or cycles, in a signal. Hertz is widely used to refer to the clock rate of a CPU; for example, 2 GHz means two billion cycles per second. The term is also used for other repeating cycles such as frame rate; for example, a 60 Hz TV displays 60 frames per second. See MHz and GHz.