Sound is psychological experience created by the brain in response to changes in air pressure received by the auditory system.

Sound

Audible waves that pass through the air or other materials and are detectable when they make contact with an individual's or an animal's auditory system.

Air Pressure

The force exerted onto a surface by the weight of the air above that surface in the atmosphere of Earth.

Auditory System

is the sensory system that is responsible for the perception of sound, including its reception, transmission, and processing.