The medium vibrates perpendicular to the direction the wave travels in a transverse wave.

Here's a simple way to remember it:

* Transverse sounds like "across", and the vibrations are indeed across the direction of the wave's motion.

* Think of a ripple in a pond: The water moves up and down (perpendicular) as the wave travels horizontally.

Examples of transverse waves include:

* Light waves

* Electromagnetic waves

* Waves on a string