In the context of sound waves, amplitude is the measure of the maximum displacement of vibrating particles in a medium from their mean position when a sound is produced. It can also be defined as the maximum displacement from the mean position to the extreme position of a particle in the medium through which a wave propagates. The amplitude of a sound wave determines its loudness, with larger amplitudes corresponding to louder sounds.
In the context of transverse waves, such as light or water waves, amplitude is a measure of the distance between a line through the middle of the wave and a crest or trough. It can also be understood as the size of the wave or the height of the wave.
