| Abbreviation | Definition |
|---|---|
| SEDP | Socio-Economic Development Plan |
| SEDREF | State Education Department Reference File |
| SEK | South East Kansas |
| SEMA | State Emergency Management Agency |
| SEMS | Standardized Emergency Management System |
| SEO | State Engineer's Office |
| SEPA | State Environmental Policy Act |
| SEPP | State Environmental Planning Policy |
| SEPTA | South Eastern Pennsylvania Transit Authority |
| SERD | State Employee Recognition Day |
| SERP | Statewide Emergency Response Plan |
| SERPS | State Earnings Related Pension Scheme |
| SERS | State Employees' Retirement System. |
| SES | State Emergency Service |
| SES | State Emergency Services |
| SETC | State Express Transport Corporation |
| SETG | South East Training Ground (fire brigade) |
| SEV | State Equalized Value |
| SEZ | Special Economic Zone |
| SF | San Francisco |