A transverse wave is a moving wave, a wave that propagates (travels) in a direction perpendicular to the direction in which the oscillations that produce the wave are moving. For example: if a transverse wave is moving in the positive x-direction, its up and down oscillations are in up and down directions that lie in the yz-plane.
A light wave is a transverse wave composed of coupled electric E and magnetic M fields oscillating in mutually perpendicular directions, while the transverse light wave itself propagates in a direction that is perpendicular to the directions of oscillation of both the electric and magnetic fields. In the illustration of a light wave, the amplitude of the E field reaches a peak at the same time that the amplitude of the M field does. The peak amplitudes of this transverse light wave can be imagined moving together to the right.
