The Wave is a propagating dynamic disturbance change from range line and quantities, sometimes as described by a wave equation. In physical waves, at least two field quantities in the wave medium are involved. Waves can be periodic, in which case those quantities oscillate repeatedly about an equilibrium resting value at some frequency. When the entire waveform moves in one direction it is said to be a traveling wave by contrast, a pair of superimposed periodic waves traveling in opposite directions makes a standing wave. In a standing wave the measure of vibration has energy of the waves position and the amplitude that appears.

The types of waves most commonly studied in classical physics are mechanical and electromagnetic. In a mechanical wave, stress and strain fields oscillate about a mechanical equilibrium. A mechanical wave is a local deformation strain in some physical medium that propagates from particle to particle by creating local stresses that cause strain in neighboring particles too. For example, sound waves are variations of the local pressure and particle motion that propagate through the medium. Other examples of mechanical waves are seismic waves, gravity waves, surface waves, string vibrations standing waves, and vortices. 

A electromagnetic wave such as light, coupling between the electric and magnetic fields which sustains propagation of a wave involving these fields according to Maxwell's equations. Electromagnetic waves can travel through a vacuum and through some dielectric media at wavelengths where they are considered transparent. Electromagnetic waves, according to their frequencies or wave lengths have more specific designations including radio waves, infrared radiation, terahertz waves, visible light, ultraviolet radiation, and gamma rays.

Mechanical and electromagnetic waves transfer energy, momentum, and information, but they do not transfer particles in the medium. In mathematics and electronics waves are studied as signals. On the other hand, some waves have envelopes which do not move at all such as standing waves which are fundamental to music and hydraulic jumps. Some, like the probability waves of quantum mechanics, may be completely static. A physical wave is almost always confined to some finite region of space, called its domain. For example, the seismic waves generated by earthquakes are significant only in the interior and surface of the planet, so they can be ignored outside it. However, waves with infinite domain, that extend over the whole space, are commonly studied in mathematics, and are very valuable tools for understanding physical waves in finite domains.

A plane wave is an important mathematical idealization where the disturbance is identical along any infinite plane normal to a specific direction of travel. Mathematically, the simplest wave is a sinusoidal plane wave in which at any point the field experiences simple harmonic motion at one frequency. In linear media, complicated waves can generally be decomposed as the sum of many sinusoidal plane waves having different directions of propagation and/or different frequencies. 

A plane wave is classified as a transverse wave if the field disturbance at each point is described by a vector perpendicular to the direction of propagation also the direction of energy transfer or longitudinal if those vectors are exactly in the propagation direction. Mechanical waves include both transverse and longitudinal waves on the other hand electromagnetic plane waves are strictly transverse.