GMT
From Longman Dictionary of Contemporary EnglishGMTGMT /ˌdʒiː em ˈtiː/ noun [uncountable] British English (Greenwich Mean Time) the time as measured at Greenwich in London, that is used as an international standard for measuring timeFrom Longman Business DictionaryGMTGMT noun [uncountable] Greenwich Mean Time; the time as measured at Greenwich in London, used as an international standard for measuring timeThe accident happened at 9.33 a.m. GMT on 14 May.