A Cooling Tower is a structure that helps remove Heat from water used as a coolant; e.g., in electric power generating plants.
Other /More definition:
A Cooling Tower is Device which dissipates the heat from water-cooled systems by spraying the water through streams of rapidly moving air.
Other /More definition:
A Cooling tower is Water-conserving cooling device in which cooling water loses heat when a portion of it is evaporated (Brown and Caldwell, 1990).