The crest of a water wave moves perpendicular to the direction the wave energy moves.
A transverse wave is a wave in which particles move up and down or side-to-side at right angles or perpendicular to the direction the wave travels.
Examples of these waves are: vibrations in strings, ripples on water surface and electromagnetic waves. In a transverse wave, the particles of the medium oscillate in a direction perpendicular to the direction of propagation.
