| Digitally Controlled Oscillator | Academic & Science |
| Digital Coherent Optics | Academic & Science |
| Deputy Chief Officer | Banking |
| Developer Certificate of Origin | Business |
| Death Certificate Only | Business |
| Ducommun, Incorporated | Business |
| Decant Oil | Chemistry |
| Dynamic Creative Optimization | Community |
| David Christopher Orchestra | Community |
| Defence Community Organisation | Community |
| Development Coordination Office | Community |
| Director Of Christian Outreach | Community |
| Data Clock Output | Computing |
| Dual Core Optimizer | Computing |
| Data Change Object | Computing |
| Device Configuration Overlay | Computing |
| Defense Cyber Organization | Computing |
| Defensive Cyberspace Operations | Computing |
| Departmental Computing Organization | Computing |
| Defensive Cyber Operations | Computing |
| Data Control | Computing |
| Digital Central Office | Computing |
| Data Center Operations | Computing |
| Doppo Corpo Orizzontali | General |
| Digital Controled oscilaltor | General |
| Developmental Center of the Ozarks | General |
| Decision Coordination Office | General |
| Data Center Observatory | General |
| Direct capture of Objectives | General |
| Deputy Commandant for Operations | General |
| Direct Commission Officer | General |
| Designated Countries of Origin | General |
| Data Center Optimized | General |
| Digital Controlled Oscillator | General |
| Defense Coordinating Officers | General |
| Dues Check Off | General |
| Doppio Corpo Orizontale | General |
| Digital Credit Observatory | General |
| Derivatives Clearing Organization | General |
| Diluted Crude Oil | General |
| Driver Controlled Operation | General |
| Decentralized Cooperative Organization | General |
| Dynamically Configurable Object | General |
| Delayed Compliance Order | General |
| Dynamic Creative Optimisation | General |
| Data Center Outsourcing | General |
| Designated Collaborating Organization | General |
| Division of Communication Outreach | General |
| Data Controller Object | General |
| Doping Control Officer | General |
| Dynamic Control and Optimization | General |
| Deputy Commander for Operation | General |
| Distilled Corn Oil | General |
| Doppio Corpo Orizzontali | General |
| Delorean Club of Ohio | General |
| Driving Condition | General |
| Derivatives Clearing Organizations | General |
| Deep Carbon Observatory | General |
| Device Configuration Overlays | General |
| District Cooperative Officer | Governmental |
| Docket Control Order | Governmental |
| Deputy Commissioner of Operations | Governmental |
| Divisional Crime Officer | Governmental |
| District Coordination Officer | Governmental |
| Data Collection Office | Governmental |
| Dental Care Organization | Medical |
| Disability Compliance Office | Medical |
| Diabetic Care Overview | Medical |
| Defense Connect Online | Military and Defence |
| Defense Coordinating Officer | Military and Defence |
| Dead Cell Operatives | Military and Defence |
| Dial Central Office | Military and Defence |
| Division of County Operations | Regional |
| Dialog Component Objects | Softwares |
| Detailed Checkout | Space Science |