December - a month of the year in the Gregorian Calendar

Digital Equipment Corporation - a computer and technology company, now part of HP

New York State Department of Environmental Conservation (DEC)

Declan Donnelly - a United Kingdom television presenter

Declination - a term from astronomy

Disasters Emergency Committee -- a group of charities in the United Kingdom who coordinate disaster relief efforts

Deč, a village in Serbia.

Diplome d’Études Collegiales - a college studies diploma issued in Quebec

Department of Environment and Conservation

Derwent Entertainment Centre The DEC - An entertainment centre in Hobart, Australia

Diethylcarbamazine - a drug commonly used to treat infections by filarial parasites

Oratorical Declamation - an event in competitive debate

DEC - ICAO airport code of Decatur Airport in Decatur, Illinois

Francis E. Dec, a conspiracy theorist