Transverse waves and longitudinal waves.

Transverse wave: In a transverse wave, particles oscillate up and down about their mean position in a direction perpendicular to the direction of propagation of wave. e.g. light waves

Longitudinal wave: In a longitudinal wave, the individual particles of the medium move in a direction parallel to the direction of propagation of the wave. The particles oscillate back and forth about their position of rest. e.g. Sound wave