| Acronym | Definition |
|---|
| SAD | Seasonal Affective Disorder |
| SAD | Sex, Alcohol, Drugs |
| SAD | Social Anxiety Disorder |
| SAD | Seek and Destroy |
| SAD | Sjedinjenih Americkih Država (Bosnian: United States of America) |
| SAD | Sons and Daughters (band) |
| SAD | Supply And Demand |
| SAD | Seaford (Amtrak station code; Seaford, DE) |
| SAD | Single Administrative Document |
| SAD | Structural Analysis and Design (engineering; various schools) |
| SAD | Separation Anxiety Disorder |
| SAD | Search and Destroy |
| SAD | South Atlantic Division (USACE) |
| SAD | Stand and Deliver |
| SAD | Standard American Diet |
| SAD | Social Affairs Department (various organizations) |
| SAD | Special Activities Division (US CIA) |
| SAD | Stay Another Day |
| SAD | Schizoaffective Disorder |
| SAD | Shiromani Akali Dal (India) |
| SAD | Security Association Database (computer security, information assurance) |
| SAD | System Architecture Diagram (computer architecture) |
| SAD | Swiss Academy for Development (foundation; Biel, Switzerland) |
| SAD | Species Abundance Distribution |
| SAD | Sudden Aspen Decline (forestry; Colorado) |
| SAD | Security Association Database |
| SAD | Security Administration |
| SAD | Service Administrative Driver |
| SAD | Stand Alone Device |
| SAD | Software Architectural Design |
| SAD | System Analysis and Design |
| SAD | Sum of Absolute Differences |
| SAD | State Active Duty (National Guard) |
| SAD | Slovenská Autobusová Doprava |
| SAD | Selected Area Diffraction |
| SAD | Sociedad Anónima Deportiva |
| SAD | School of Architecture and Design |
| SAD | Subacromial Decompression |
| SAD | Southern Area District (US FEMA) |
| SAD | Statutory Audit Directive |
| SAD | Sierra Army Depot |
| SAD | Sorry About Dresden (band) |
| SAD | Single Awareness Day (slang for Valentine's Day) |
| SAD | Seizure-Alert Dog |
| SAD | Scotland Against Drugs (UK) |
| SAD | Solar Array Drive |
| SAD | Safety Assessment Document |
| SAD | Silicon Avalanche Diodes |
| SAD | Supplementary Access Device (special pass) |
| SAD | Software Architecture Description |
| SAD | Sistema de Adquisición de Datos (Spanish: Data Acquisition Systems) |
| SAD | Salon des Artistes Décorateurs (French art group) |
| SAD | Source Axis Distance |
| SAD | Stanford Athletic Department (Stanford University) |
| SAD | Sistema Acquisizione Dati (Italian: Data Acquisition System) |
| SAD | Sullen, Angry, Depressed |
| SAD | Small Area Data |
| SAD | Summary of Aggregated Deficiencies (audit) |
| SAD | System Architecture Document |
| SAD | Serial Analog Delay |
| SAD | Stand Alone Dump |
| SAD | Safety Analysis Document |
| SAD | System Activity Display (IBM) |
| SAD | Speech Activity Detector |
| SAD | Small Angle Diffraction |
| SAD | Security Association Data |
| SAD | Senior Air Director |
| SAD | Sjedinjene Amerièke Države (Croatian: United States of America) |
| SAD | Safety & Arming Device |
| SAD | Software Assembly Descriptor |
| SAD | Splitter-And-Delivery (network architecture) |
| SAD | Seniors Against Discrimination |
| SAD | Summary of Audit Differences |
| SAD | Single, Available, and Desperate |
| SAD | Southern African AIDS Trust |
| SAD | Situation Awareness Display |
| SAD | System Allocation Document |
| SAD | System Analyst Designer |
| SAD | Stock Assessment Driven (fisheries) |
| SAD | Scan Axis Directionality |
| SAD | System Administrator/Administration |
| SAD | system application design |
| SAD | Self-Aware Data |
| SAD | Station Address Directory |
| SAD | Safety Analysis Diagram |
| SAD | Static Airbag Deployment |
| SAD | Solution Architecture Document |
| SAD | Service Application Description |
| SAD | Station Arrival Date |
| SAD | Safety Assurance Diagram |
| SAD | Staging Area Director |
| SAD | Students Against Destruction |
| SAD | Square Air Diffuser |
| SAD | Special Artificer, Special Synthetic Training Devices (US Navy) |
| SAD | Special Assignment Division |
| SAD | Special Asset Department |
| SAD | Submarine Anomaly Detection |
| SAD | Site Adaption Data (FAA ARTCC configuration of site resources) |
| SAD | Special Activities Directorate |
| SAD | Standard Auto Discount (insurance) |
| SAD | Status Advisory Display |
| SAD | Shock Advisory Defibrillation (medical treatment) |
| SAD | Symptomatic Abdominal Distension |
| SAD | Support Air Direction |
| SAD | Supplementary Alteration Drawing |
| SAD | Systems Architectural Directorate |
| SAD | Structured ASCI Design |
| SAD | System Appreciation Document |