From Longman Business Dictionaryexternalityex‧ter‧nal‧i‧ty /ˌekstɜːˈnæləti-ɜːr-/ noun (plural externalities) [countable usually plural] ECONOMICS something that is not directly connected to an industrial process or economic activity but has an effect on itClean-air rules are all about what economists call externalities, with one person’s pollution causing problems for others.
