Amplitude is the measure of the "intensity" or "size" of a wave.

• In Acoustic Sound: Amplitude corresponds to the magnitude of the variation in air pressure. In practice, we perceive it as volume. A sound with a large amplitude is a loud sound; a sound with a low amplitude is a low sound.

• In Electrical Signals: Amplitude refers to the voltage or power level of the audio signal. This is what we see represented graphically on the screen of a DAW (Digital Audio Workstation) — high peaks indicate high amplitude.