Sound: Pressure Waves Propagated Through Fluids and Solids, That are Detected by the Organs of Hearing.
Air vibrates. It is continually set in motion by natural forces (the wind, the sea), by animals and by people. The human ear can detect those vibrations and the brain understands them as sound. Sound facilitates communication and is a medium for pleasure and joy. Yet sound can also create a nuisance and be detrimental to health and wellbeing.
When designing buildings it is not possible to eliminate noise, but by attending to the physics of sound we should be able to strike out (or at very least, reduce) the nuisance, ...