outfall /ˈaʊtˌfɔl/noun 3verb 1forms 4 noun3 •The point or place of discharge of a river, drain, culvert, sewer, etc.; mouth; embouchure.The rules focus primarily on two crucial operating features: seawater intakes and outfalls. — 2014 •(dialect) A quarrel; a falling out. •(no longer used) A sudden eruption of troops from a fortified place; sally. verb1 •(no longer used) To burst forth, as upon an enemy; make a sally. formsoutfell · outfallen · outfalling · outfalls