From Longman Dictionary of Contemporary EnglishSTDSTD /ˌes tiː ˈdiː/ noun [countable, uncountable] medical MI (sexually transmitted disease) a disease that one person passes to another through having sex, such as AIDS or herpesFrom Longman Business DictionarySTDSTD noun [uncountable] subscriber trunk dialling; in Britain, the name for the former telephone system that allowed people to connect their own long-distance calls by using an STD code (=a special number for the area you are calling). Officially, STD codes are now called area codes although many people still use the old namestd.std. written abbreviation for standard
