| Abbreviation | Definition |
|---|---|
| SYG | Secretary General (UN) |
| SYG | Secretary General of the United Nations |
| SYH | Save Your Hide |
| SYNC | Synchronization |
| SYP | Six Year Plan |
| SYQ | Command and Control Systems |
| SYQ-20 | Advanced Combat Direction System |
| SYQ-7 | NAVMACS system |
| SYS | See Your Service |
| SYS | System |
| SYSCOM | Systems Command |
| SYSCON | System Control |
| SYSCON | System Control Center |
| SYSEX | System Exerciser |
| SYSGEN | System Generation |
| SYSTO | Systems Staff Officer |
| SYW | Seven Years War |
| SZ | Surf Zone |
| SZD | Szybowcowy Zaklad Doswiadczalny (Experimental Glider Establishment) |
| SZE | Security Zone Entry |