High frequency refers to a range of electromagnetic waves or sound waves that oscillate at a high rate. In the context of radio waves, high frequency (HF) typically ranges from 3 to 30 megahertz (MHz). These waves are used for various applications, including amateur radio, aviation communication, and shortwave broadcasting. In sound, high frequency describes sounds with a high pitch, such as a whistle or a bird chirping. Frequencies above 2,000 hertz (Hz) are generally considered high frequency in audio. High-frequency sounds are important in music and speech, as they contribute to clarity and detail in sound perception.