Definitions for "Potential evaporation"
The amount of water that would be evaporated from a land or water surface if the water supply were unlimited, as opposed to actual evaporation. The latter will fall below the former when the water at the evaporating surface is somehow limited.
Rate of evaporation of water from the landscape back into the atmosphere. The potential evaporation is taken to be proportional to the rate at which water evaporates from a purpose-built pan located at the Earth's surface, known as pan evaporation.
Same as evaporative power.