| D | Deci | - | Astronomy |
| D | Deuterium | - | Astronomy |
| D&D | Dungeons And Dragons - Diversion And Distress (Air Traffic Control) | - | Astronomy |
| D/B/A | Doing Business As | - | Astronomy |
| DA | Danish Language (ISO 639-1 Code) - Deca | - | Astronomy |
| DA | Denmark (FIPS 10-4 Country Code) -U.S. Department Of The Army - District Attorney | - | Astronomy |
| DA&M | (U.S.) Director | - | Astronomy |
| DACT | Data Automated Communications Terminal - Dissimilar Air Combat Training | - | Astronomy |
| DADVSI | Loi Sur Le Droit D?auteur Et Les Droits Voisins Dans La Soci?t? De L?information (French | - | Astronomy |
| DAES | Defence Acquisition Executive Summary - (UK MoD) Directorate Of Analysis | - | Astronomy |
| DAF | Dissolved Air Flotation | - | Astronomy |
| DAFIF | Digital Aeronautical Flight Information File | - | Astronomy |
| DAK | Disney's Animal Kingdom | - | Astronomy |
| DAN | Danish Language (ISO 639-2 Code) | - | Astronomy |
| DAO | Division Ammunition Officer | - | Astronomy |
| DAQ | Data Acquisition -Delivered Audio Quality | - | Astronomy |
| DARO | (U.S.) Defense Airborne Reconnaissance Office | - | Astronomy |
| DARPA | U. S. Defense Advanced Research Projects Agency | - | Astronomy |
| DART | Disaster Assistance Response Team - Dublin Area Rapid Transit | - | Astronomy |
| DAS | Defensive Aids Suite | - | Astronomy |
| DASD | (U.S.) Deputy Assistant Secretary Of Defense | - | Astronomy |
| DASL | Datapoint's Advanced System Language | - | Astronomy |
| DAU | (U.S.) Defense Acquisition University | - | Astronomy |
| DAWN | (U.S.) Drug Abuse Warning Network | - | Astronomy |
| DB | Database - Deutsche Bahn | - | Astronomy |
| DB | Decibel | - | Astronomy |
| DB | Dubnium | - | Astronomy |
| DBA | De Bellis Antiquitatis (miniature Wargaming Rules) | - | Astronomy |
| DBBL | (U.S. Army Simulation Center) Dismounted Battlespace Battle Laboratory | - | Astronomy |
| DBCS | Double-Byte Character Set | - | Astronomy |
| DBDO | Desert BDO | - | Astronomy |
| DBE | Dame Commander Of The Order Of The British Empire | - | Astronomy |
| DBF | Detection By Fire (weapon Launch Signature) | - | Astronomy |
| DBM | De Bellis Multitudinis (miniature Wargaming Rules) - Detection By Movement (military Target) | - | Astronomy |
| DBR | De Bellis Renationis (miniature Wargaming Rules) | - | Astronomy |
| DBS | Direct Broadcast Services (television) | - | Astronomy |
| DC | Da Capo - Italian Democrazia Cristiana - Digital Compass - Direct Current -District Of Columbia (postal Symbol) -Douglas Aircraft Company - Dublin Core - Duty Cycle | - | Astronomy |
| DCA | Defensive Counter Air ?DiChloroAcetate -Ronald Reagan Washington National Airport (IATA Code) | - | Astronomy |
| DCAA | (U.S.) Defense Contract Audit Agency | - | Astronomy |
| DCAS | Devon And Cornwall Archery Society | - | Astronomy |
| DCC | Dallas Christian College | - | Astronomy |
| DCC | Digital Command Control (model Railroading) - Direct Client-to-Client (Internet Relay Chat) - Dismounted Close Combat | - | Astronomy |
| DCCP | Datagram Congestion Control Protocol | - | Astronomy |
| DCD | [Organ] Donation After Cardiac Death | - | Astronomy |
| DCE | Data Communication Equipment | - | Astronomy |
| DCFC | Death Cab For Cutie | - | Astronomy |
| DCI | Detection | - | Astronomy |
| DCIM | Digital Camera Images | - | Astronomy |
| DCIMS | Dental Classification Information Management System - Dismounted Combat Identification Marking System | - | Astronomy |
| DCOM | Disney Channel Original Movie | - | Astronomy |
| DCOP | Desktop Communication Protocol | - | Astronomy |
| DCSOPS | Deputy Chief Of Staff For Operations And Plans | - | Astronomy |
| DCW | Digital Chart Of The World | - | Astronomy |
| DCYSC | Discovery Channel Young Scientist Challenge | - | Astronomy |
| DD | Many | - | Astronomy |
| DDA | Digital Differential Analyzer - Deputy District Attorney | - | Astronomy |
| DDD | Data Display Debugger - Digital Digital Digital (CD Mastering) | - | Astronomy |
| DDL | Digital Data Link | - | Astronomy |
| DDN | U.S. Defense Data Network | - | Astronomy |
| DDOS | Distributed Denial Of Service | - | Astronomy |
| DDR | Dance Dance Revolution - Deutsche Demokratische Republik (German | - | Astronomy |
| DDR&E | (U.S.) Director Of Defense Research And Engineering (1958?1978) | - | Astronomy |
| DDS | Doctor Of Dental Surgery | - | Astronomy |
| DDT | Dichloro-Diphenyl-Trichloroethane (insecticide) - Dynamic Debugging Tool (computing) | - | Astronomy |
| DE | Delaware (postal Symbol) - Germany (ISO 3166 Digram) | - | Astronomy |
| DE | German Language (ISO 639-1 Code) | - | Astronomy |
| DEA | Drug Enforcement Agency | - | Astronomy |
| DEC | Department Of Environmental Conservation - Digital Equipment Corporation - Disasters Emergency Committee | - | Astronomy |
| DECA | (U.S.) Defense Commissary Agency | - | Astronomy |
| DECSIM | Model DEComposition And SIMulation Algorithm - Directed Energy Combat SIMulation | - | Astronomy |
| DECT | Digital European Cordless Telephone | - | Astronomy |
| DEFCON | Defence Readiness Condition | - | Astronomy |
| DEFRA | (UK) Department For Environment | - | Astronomy |
| DEM | Data Exchange Mechanism - Digital Elevation Model | - | Astronomy |
| DEPSECDEF | (U.S.) Deputy Secretary Of Defense | - | Astronomy |
| DERA | British Defence Evaluation And Research Agency (1995?2001) | - | Astronomy |
| DES | Deep Ecliptic Survey | - | Astronomy |
| DEU | German Language (ISO 639-2 Code) | - | Astronomy |
| DEU | Germany (ISO 3166 Trigram) | - | Astronomy |
| DF | Direct Fire - Direction Finding | - | Astronomy |
| DFAD | Digital Feature Analysis Data (dee-fad) | - | Astronomy |
| DFAS | (U.S.) Defense Finance And Accounting Service | - | Astronomy |
| DFB | Deutscher Fu Ball-Bund (German For German Football Association) | - | Astronomy |
| DFCB | Data Format Control Book | - | Astronomy |
| DFID | UK Department For International Development | - | Astronomy |
| DFM | Dynamic Flowgraph Methodology | - | Astronomy |
| DFSP | Dermatofibrosarcoma Protuberans | - | Astronomy |
| DG | Dei Gratia (Latin | - | Astronomy |
| DGA | Direction G?n?rale Des Arm?es (French Armed Forces General Directorate) | - | Astronomy |
| DGD&D | UK Directorate General Of Development And Doctrine | - | Astronomy |
| DGPS | Differential GPS | - | Astronomy |
| DGZ | Desired Ground Zero | - | Astronomy |
| DH | Dear Husband (increasingly Prevalent On Social Mailing Lists | - | Astronomy |
| DHA | DocosaHexaenoic Acid | - | Astronomy |
| DHHS | (U.S.) Department Of Health And Human Services | - | Astronomy |
| DHL | Dalsey | - | Astronomy |
| DHRA | (U.S.) DoD Human Resources Activity | - | Astronomy |
| DHS | U.S. Department Of Homeland Security | - | Astronomy |
| DHSS | UK Department Of Health And Social Security | - | Astronomy |
| DHY | Dahomey (ISO 3166 Trigram; Became BEN In 1977) | - | Astronomy |
