DEC, dec or Dec may refer to:
Abbreviations, initialisms, acronyms December, the 12th month and final month of the year in the Julian and Gregorian calendars Decade (log scale), a unit for measuring ratios on a logarithmic scale Declination, a term from astronomy Diethylcarbamazine, an anti-parasite drug Diethyl carbonate, an organic solvent Diplome d’Études Collegiales, French name for Diploma of College Studies, a college studies diploma issued in Quebec Oratorical Declamation, an event in competitive debate Display Energy Certificate, a UK requirement to show a certificate rating energy performance in public buildings Direct energy conversion, a scheme for power extraction from nuclear fusion An abbreviation for decimal, for example in ASCII charts Abbreviation for decathlon, an Olympic athletics event Decorated Gothic, a style of church architecture
Organizations Delaware Electric Cooperative Department of Education and Communities (New South Wales), Australia Department of Environment and Conservation (New South Wales), Australia Department of Environment and Conservation (Western Australia), Australia New York State Department of Environmental Conservation, New York, United States Dheeraj and East Coast LLC, Dubai Digital Equipment Corporation, a defunct computer and technology company Disasters Emergency Committee, coordinates fifteen disaster relief charities in the United Kingdom Distance Education Council, former body for open and distance education, see Distant Education Bureau Dubai Economic Council, a policy-making body of the government of Dubai
People Declan Donnelly (from Ant & Dec), a United Kingdom television presenter Francis E. Dec (1926–1996), American outsider writer and lawyer
Places Deč, a village in Serbia Decatur Airport, Decatur, Illinois (IATA airport code DEC) Derwent Entertainment Centre, an entertainment centre in Hobart, Australia Doncaster Education City, a development in South Yorkshire