A kilohertz (abbreviated as “kHz”) is around 1,000-hertz. Like Hertz, kilohertz is also used to measure frequency or cycles per second. Since one Hertz is one cycle per second, one kilohertz is about 1,000 cycles per second.
Kilohertz is used to measure frequencies of sound waves since the audible spectrum has sound frequencies between about 20 Hz to 20 kHz.
For example, middle C (C4) produces a piano keyboard with a frequency of about 261.63 Hz. Whereas the C key is above two octaves that produce middle C (C6), it produces a frequency that is more than just 1 kHz (1,046.5 Hz).
Since the sound frequency is double with each octave, the C7 key produces an audible frequency over 2 kHz (2,093 Hz). Now you must have guessed that frequencies higher than 2 kHz sound are more high-pitched.
Sound waves and low-frequency radio waves are often measured in kilohertz. Other waves, such as high-frequency radio waves, visible light waves, and ultraviolet rays, are all higher frequencies. So most waves, in an electromagnetic spectrum are measured by megahertz, gigahertz, or larger units of measurements.