1. the area of land from which water drains into a river, lake, or reservoir
Usage: also called a watershed or drainage basin; commonly used in geography and environmental science
2. the area served by a particular institution, such as a school or hospital
Usage: British usage; refers to the population or region from which an institution draws its users or students

Examples

• The catchment area of the Amazon River is the largest in the world.
• Heavy rainfall in the catchment increased the water level in the reservoir.
• The school's catchment includes three neighboring villages.
• Engineers studied the catchment to understand flood patterns.
• The hospital serves patients from a wide catchment area.
• Pollution in the catchment affects the quality of drinking water downstream.