Definition: A kilohertz (symbol: kHz) is a unit of frequency equal to one thousand (1000) hertz (Hz). The hertz, in turn, is the SI unit of frequency, defined as one cycle per second.

History/origin: The kilohertz is derived from the hertz, named after the German physicist Heinrich Hertz, who made significant contributions to the understanding of electromagnetic waves. The prefix 'kilo-' denotes a factor of 10³, adhering to the SI system of units.

Current use: Kilohertz is used to measure frequencies in the range of audio signals, radio waves (particularly AM radio), and some computer hardware components. It is a common unit in electronics, telecommunications, and signal processing.