point source > define
noun
- A concentrated source (especially of radiation or pollution) that is spatially constricted. .
by WordNet 3.0 © 2006 by Princeton University
point source is a stationary location or fixed facility such as an industry or municipality that discharges pollutants into the air or surface water through pipes, ditches, lagoons, wells, or stacks - a single identifiable source such as a ship or a mine.