| S/o | Son of 
| Others |
| S/O | Switchover
| Others |
| S/P | Serial to Parallel
| Others |
| S/P | Signal Processor
| Others |
| S/P | Status Post
| Others |
| S/P | Staus Post
| Others |
| S/P | Suspected
| Others |
| S/PDIF | Sony/Philips Digital Interface Format
| Others |
| S/R | Shift Register
| Others |
| S/R | Stimulus/Response
| Others |
| S/R | Streaks and Recents
| Others |
| S/R | Su Referencia
| Others |
| S/RTF | Search and Recovery Task Force
| Others |
| S/S | Samples per Second
| Others |
| S/S | Saying Sh*t
| Others |
| S/S | Seconds per Step
| Others |
| S/S | Shout-out for Shout-out
| Others |
| S/S | Single Sideband
| Others |
| S/S | Slipper Spoon
| Others |
| S/S | Souvenie Sheet
| Others |
| S/S | Souvenier Sheet
| Others |
| S/S | Space Shuttle
| Others |
| S/S | Spreadsheet
| Others |
| S/S | Steamship
| Others |
| s/s | stepson
| Others |
| S/S | SubSystem
| Others |
| S/S | SuperSeeds
| Others |
| S/SI | Simulation and System Infrastructure
| Others |
| S/SIS | Sales/Service Information System
| Others |
| S/SU/AC | Systems/ Systems Upgrades and Advanced Concepts
| Others |
| S/T | Pseudo-Ternary
| Others |
| S/U | Set Up
| Others |
| S/U | Slide Up
| Others |
| S/UIQ | Simplified Urinary Impact Questionnaire
| Others |
| S/V | Sailboat
| Others |
| S/V | Space Vehicle
| Others |
| S/V | Supply Valve
| Others |
| s/w | shrinkwrapped (plastic)
| Others |
| S/W | Spike-and-Wave
| Others |
| S/W | Spoke With
| Others |
| S0 | ISYSCON Workstation class computer unit (TCU or HCU)
| Others |
| S1 | Seaman 1st Class
| Others |
| S1 | Shuttle 1
| Others |
| S1 | Starboard 1
| Others |
| S12H | Sepang Twelve Hours
| Others |
| S173AB | Society of the 173rd Airborne Brigade
| Others |
| S1ID | Society of the 1st Infantry Division
| Others |
| S1K | S1000 Simnet Format
| Others |
| S1K | Sepang 1000 Kilometers
| Others |
| S1SB | Audi S1 Sportback
| Others |