Wave height refers to the vertical distance between the crest (high point) and trough (low point) of a wave. It is typically measured from the average level of the water surface to the highest point of the wave's face, or from the lowest point on the wave's face to the deepest part of the trough. Wave height can vary depending on weather conditions, ocean currents and wind speed, among other factors. It is an important factor in determining sea state, which refers to the overall condition of the sea surface, including wave height, period (time between crests), direction, and energy.