Here's why:

* Transverse Waves: In transverse waves, the oscillations of the medium (or the electromagnetic field in the case of light) are perpendicular to the direction the wave travels.

* Light Waves: Light waves are made up of oscillating electric and magnetic fields. These fields oscillate perpendicular to the direction the light wave travels.

Think of a rope tied to a post. If you shake the rope up and down, the waves that travel along the rope are transverse. The rope oscillates up and down (perpendicular to the rope's length), and the waves travel horizontally along the rope.