Outfall/ˈaʊtfɔːl/ Definition 1 of 2Pro Tip 1/3Watercourse Ending Refers to the final segment where water flows from a smaller channel into a larger body. The outfall of the creek is a popular fishing spot. Pro Tip 2/3Pollution Concern Outfall can be a source of pollution, implying environmental concerns when mentioned. Activists protested near the factory's outfall. Pro Tip 3/3Engineering Term Commonly used in civil engineering when discussing water management systems. The engineers designed a new outfall to prevent flooding.