| Abbreviation | Definition |
|---|---|
| RVE | Redundant Vector Elimination |
| RVQ | Residual Vector Quantization |
| RVR | Recursive Variance Reduction |
| RW | Random Walk |
| RWQ | Regionwise Quadratic Model |
| RWT | Reciprocal- Wedge Transform |
| RXT | Rate times Time |
| RYI | Revised Yale Isochrone |
| RYR | Reject outside of Y Range |
| RZX | Return to Zero for any X |
| S | Side |
| S | Sin |
| S | Stieltjes |
| S | Sum |
| S | Supercardiod |
| s.d. | standard deviation |
| SA | Sheet of Assertion |
| SA | Short Arc |
| SA | Solo Axis |
| SA | Souslin's Axiom |