The amplitude of a wave is the maximum displacement of a particle in the wave from its equilibrium position. In simpler terms, it refers to the height or depth of a wave from its rest position to its highest or lowest point. For example, in an ocean wave, the amplitude would be the distance from the water level at rest to the crest (highest point) of the wave or to the trough (lowest point) of the wave. The greater the amplitude of a wave, the more energy it carries.