| Acronym | Definition |
|---|
| S3 | Simple Storage Service (Amazon service) |
| S3 | Heart Sounds |
| S3 | Self-Sustaining Systems (workshop) |
| S3 | Secondary 3 (various locations) |
| S3 | Swiss Space Systems |
| S3 | Silicon and Software Systems |
| S3 | Signals, Sensors and Systems (Royal Institute of Technology, Stockholm, Sweden) |
| S3 | Silverstream Software |
| S3 | Scream Trilogy (movies) |
| S3 | Solid Snake Simulation (Metal Gear Solid 2: Sons of Liberty game) |
| S3 | Selection for Societal Sanity (Metal Gear Solid 2: Sons of Liberty game) |
| S3 | Strategic Services Sourcing Contract (US Army Communications-Electronics Life Cycle Management Command) |
| S3 | Secure Software Systems |
| S3 | Sleep Mode 3 (deep-sleep computer power-down state) |
| S3 | Soils, Sediment and Subsurface Inc (Tallahassee, FL) |
| S3 | Spectrum Supportability System (US DoD Defense Information Systems Agency) |
| S3 | Operations & Training Officer |
| S3 | Safety and Suitability for Service (NATO munitions) |
| S3 | Start-up Number Three (S3, Inc., Santa Clara, CA; founded 1989) |
| S3 | Surgery Scheduling System (Army medical department) |
| S3 | Synergistic Strike System |
| S3 | Special Sensor System |