Sound is an oscillation in pressure, stress particle displacement, particle velocity in a medium ? in room temperature. (In air speed of sound is 1125?/second or one mile in 5 seconds.) Sound produces an auditory sensation caused by the oscillation.<br><br>Moving pressure variations in air caused by something vibrating between 20 times a second and 20,000 times a second or similar variations in other substances like water. Also refers to any audio signal regardless of its energy form.