From Longman Dictionary of Contemporary Englishgarbage in, garbage outgarbage out garbage ingarbage in, garbage outused to say that if the data (=information) you put into a computer is bad, the results you get back will be bad, even if the computer program you use works properly → garbageFrom Longman Business Dictionarygarbage in, garbage outgarbage ˌin, garbage ˈout written abbreviation GIGOCOMPUTING used to say that if you put bad information into a computer, you will get bad results