Transverse wave

A transverse wave is a moving wave that consists of oscillations occurring perpendicular to the direction of energy transfer. If a transverse wave is moving in the positive x-direction, its oscillations are in up and down directions that lie in the y-z plane.

If you anchor one end of a ribbon or string and hold the other end in your hand, you can create transverse waves by moving your hand up-and-down. Notice though, that you can also launch waves by moving your hand side-to-side. This is an important point. There are two independent directions in which wave motion can occur.

In this case, these are the y and z directions mentioned above.
Further, if you carefully move your hand in a clockwise circle, you will launch waves that describe a left-handed helix as they propagate away.
Similarly, if you move your hand in a counter-clockwise circle, a right-handed helix will form.

These phenomena of simultaneous motion in two directions go beyond the kinds of waves you can create on the surface of water; in general a wave on a string can be two-dimensional. Two-dimensional transverse waves exhibit a phenomenon called polarization

A wave produced by moving your hand in a line, up and down for instance, is a linearly polarized wave, a special case.
A wave produced by moving your hand in a circle is a circularly polarized wave, another special case.
If your motion is not strictly in a line or a circle your hand will describe an ellipse and the wave will be elliptically polarized.

The transverse plane wave animation shown is also an example of linear polarization. The wave shown could occur on a water surface.

Transverse waves are waves that are moving perpendicular to the direction of vibration.

Examples

Examples of transverse waves include seismic S (secondary) waves, and the motion of the electric (E) and magnetic (M) fields in an electromagnetic plane wave, which both oscillate perpendicularly to each other as well as to the direction of energy transfer. Therefore an electromagnetic wave consists of two transverse waves, visible light being an example of an electromagnetic wave. See electromagnetic spectrum for information on different types of electromagnetic wave.

An oscillating string is another example of a transverse wave; a more everyday example would be an audience wave.