| S/C | Signal Conditioner 
| Others |
| S/C | Signal-to-Clutter
| Others |
| S/C | Software Contractor
| Others |
| S/C | Sort Code
| Others |
| S/C | Spacecraft
| Others |
| S/C | Splitter/Combiner
| Others |
| S/C | Stabilization and Control
| Others |
| S/C | StripChart
| Others |
| S/C | Sub-Contractor
| Others |
| s/c | subcutaneous(ly)
| Others |
| S/C | Supercharged
| Others |
| S/C+N | Signal-to-Clutter Plus Noise
| Others |
| S/CONT | Self Contained
| Others |
| S/D | Source/Drain
| Others |
| s/d | stepdaughter
| Others |
| S/D/W/H/o | Son/Daughter/Wife/Husband of
| Document, Banking, Legal |
| S/E | Side Effect
| Others |
| S/EOS | Standard Earth Observation Satellite
| Others |
| S/EWCC | Signals Intelligence/electronic Warfare Coordination Center
| Others |
| S/EWOC | Signals Intelligence/electronic Warfare Operations Center
| Others |
| S/F | Safety Factor
| Others |
| S/F | Single Flow
| Others |
| S/G | Strain Gage
| Others |
| S/H | Self-Help
| Others |
| S/H | Shipping / Handling
| Others |
| S/L | SearchLight
| Others |
| S/L | Shop/Laboratory
| Others |
| S/L | Squadron Leader
| Others |
| S/M | Scheduled Maintenance
| Others |
| S/M | Service/Maintenance
| Others |
| S/M | Structural/Mechanical
| Others |
| S/M | SubMarine
| Others |
| S/M | Systems management
| Others |
| S/M/W Business | Small/Minority/Women-owned Business
| Others |
| S/MIME | Secure Multipurpose Internet Mail Extensions
| Others |
| S/MIME | Secure/Multipurpose Internet Mail Extensions
| Others |
| S/N | Signal to Noise
| Others |
| S/N | Signed and Numbered
| Others |
| S/NDS | Supplemental / New Drug Submission
| Others |
| S/O | Section Officer
| Others |
| S/O | Security Officer
| Others |
| S/O | Seller's Option
| Others |
| S/O | Shipowner
| Others |
| S/O | Shipping Order
| Others |
| S/O | Shout Out
| Others |
| S/O | Shout-Out
| Others |
| S/O | Shutoff
| Others |
| S/O | Significant Other
| Others |
| S/O | Sold Out
| Others |
| S/O | Sold-Out
| Others |