Explanation of what is sound in common sense and scientific terms.

Hearing is one, the auditory, of the traditional five senses, and refers to the ability to detect sound.

Sound pressure p (or acoustic pressure) is the measurement in pascals of the root mean square (RMS) pressure deviation (from atmospheric pressure) caused by a sound wave passing through a fixed point.

Particle displacement or particle amplitude ξ is a distance measurement in m (metre) of the movement of a particle(real or imagined) in a medium as it transmits a wave.

Particle velocity is the velocity of a particle(real or imagined) in a medium as it transmits a wave.

Longitudinal waves, also referred to as compressional waves or pressure waves, are waves that have vibrations along or parallel to their direction of travel and can be a wave in which the motion of the medium is in the same direction to the motion of the wave.

The wavelength is the distance between repeating units of a wave pattern.

Amplitude is a nonnegative scalar measure of a wave's magnitude of oscillation.

Sound pressure level (SPL) is a logarithmic measure of the energy of a particular noise relative to a reference noise source.

Although it is widely used as a measure of the loudness of sound, the decibel is more generally a measure of the ratio between two quantities, and can be used to express a wide variety of measurements in acoustics and electronics.

Velocity is a vector measurement of the rate and direction of motion.

Pure tone is a single frequency tone with no harmonic content (no overtones).

An overtone is a sinusoidal component of a waveform, of greater frequency than its fundamental frequency.

In acoustics and telecommunication, the harmonic of a wave is a component frequency of the signal that is an integer multiple of the fundamental frequency.

Additive synthesis is a technique of audio synthesis which creates musical timbre.