In reference to sound, frequency is the rate at which a vibration occurs that makes up a sound wave. The faster the vibration, the higher the frequency, or pitch, of the sound is. The slower the rate of vibration, the lower the frequency, or pitch, of the sound. Frequency is measured is Hertz (Hz). Hearing is charted on a graph in relation to loudness (decibels) and frequency (Hertz).
Everyday Hearing > Frequency