| Abbreviation | Definition |
|---|---|
| RRQM/S | Read ReQuests Merged per Second |
| Rs/KG | Rupees per Kilogram |
| RT | Refrigeration Ton |
| RTU | Rambo Trade Unit |
| RU | Radiance Unit |
| RU | Relative Units |
| RU | Resonance Units |
| RVU | Relative Value Unit |
| S | Sagans (Billions and Billions) |
| S | Seconds |
| S | Shares |
| S | Siemans (inverse of Ohms - unit of admittance) |
| S | Slice |
| S | Square |
| SAE | Standard American Equivalent |
| SCC | Single-Column Centimeter |
| SCC | Standard Cubic Centimeter |
| SCCM | Standard Cubic Centimeters per Minute |
| SCF | Standard Cubic Feet |
| SCFM | Standard Cubic Feet per Minute |