The geographical area draining into a river or reservoir; SYN. catchment basin, drainage area, drainage basin.
In earth sciences, the area from which water is collected by a river and its tributaries. In the social sciences the term may be used to denote the area from which people travel to obtain a particular service or product, such as the area from which a school draws its pupils.
Or catchment area; The area of land drained by a river and its tributaries. The edge of a drainage basin is called the watershed.