| Abbreviation | Definition |
|---|---|
| S&TI | Scientific and Technical Intelligence |
| S&W | Smith & Wesson |
| S.530 | Super 530 Missile |
| S/A | Semiactive |
| S/B | Stay Behind |
| S/C | Signal-to-Clutter |
| S/C+N | Signal-to-Clutter Plus Noise |
| S/EWCC | Signals Intelligence/electronic Warfare Coordination Center |
| S/EWOC | Signals Intelligence/electronic Warfare Operations Center |
| S/L | SearchLight |
| S/L | Squadron Leader |
| S/N | Serial Number |
| S/N | Signal to Noise |
| S/N | Signal-to-Noise Ratio |
| S/RTF | Search and Recovery Task Force |
| S/S | Steamship |
| S/SU/AC | Systems/ Systems Upgrades and Advanced Concepts |
| S/T | Short Ton |
| S/V | Sailboat |
| S0 | ISYSCON Workstation class computer unit (TCU or HCU) |