externality The impact of a transaction between two parties (individuals, business firms, government) upon a third, uninvolved party. Related Related Articles: What We Can Learn From An Olympic MedalA New Kind of Grape PickerA Non-Scents Review on AmazonWhy Congestion Pricing Is a ProblemThe Great Lego Spill Ann Mills Share This Previous Articleeconomic growth Next Articlehorizontal integration December 17, 2020