| s | son |
| SAS | Special Air Service |
| Sch | School |
| SEC | Security Exchange Commission |
| Serv | Service |
| Sgt | Sergeant |
| sis | sister |
| SJ | Society of Jesus |
| slr | solicitor |
| SMU | Southern Methodist U |
| Soc | Society |
| Sqdn | Squadron |
| Sr | Senior |
| STD | Doctor of Sacred Theology |
| stepf | stepfather |
| Supt | Superintendant |
| Surg | Surgeon |