It's commonly used to measure the frequencies of audible sounds, as well as in the fields of telecommunications, broadcasting, and electronics. 

• Definition: One kilohertz represents 1,000 cycles per second. The term "hertz" is used to describe the number of cycles per second of a periodic phenomenon, with one hertz equating to one cycle per second.

• Audible Sound Frequency: In terms of sound frequencies, the human ear can typically hear sounds ranging from approximately 20 Hz to 20 kHz. Higher frequencies within this range are usually perceived as higher-pitched sounds.

• Signal Processing: In signal processing, kHz is a common unit for sampling rates of audio signals. For instance, a standard CD audio has a sampling rate of 44.1 kHz.

• Historical Context: The use of kilohertz as a frequency measurement became standard in the early 20th century with the development of radio and electronic technology.

Understanding kilohertz is important in various technical fields, especially those dealing with sound, radio transmission, and electronic circuitry, as it provides a measure of how frequently a signal or sound wave oscillates.