| Abbreviation | Definition |
|---|---|
| SDI | Semi Direct Injection |
| SDI | Strategic Driver Information |
| SDLV | Shuttle-Derived Launch Vehicle |
| SDOT | Seattle Department of Transportation |
| SDOT | Stupidly Destroying Optimum Transportation |
| SDR | Service Difficulty Report |
| SDRS | Standardized Delay Reporting System |
| SDTS | Student Disability Transportation Service |
| SDU | Super-Duty Underlift tow truck |
| SDV | Self Driving Vehicle |
| SDV | Space Delivery Vehicle |
| SDWT | Summer DeadWeight Tonnes |
| SE | Single Engine |
| SE | Standard Engine |
| SE | Street Edition |
| SEA | Seattle - Tacoma International Airport |
| SEABEE | Sea Barge Carrying Ships |
| SEC | Saturn Eclipse And Civic |
| SEC | Spoiler Elevator Computer |
| SECRET | South East Chicago Rail Enhancement Team |