| Abbreviation | Definition |
|---|---|
| RAA | Research in Astronomy and Astrophysics |
| RAI | Resident Assessment Instrument |
| RAL | Rutherford Appleton Laboratory |
| RAP | Reliable Acoustic Path |
| RAP | Roentgen Area Product |
| RB | Rigid Body |
| RBMK | Reactor Bolshoi Moshchnosti Kanalni |
| RBNP | Reverse Brazil Nut Problem |
| RBS | Rutherford Back-Scattering |
| RBUU | Relativistic Boltzmann-Uehling-Uhlenbeck |
| RC | Radiative Correction |
| RC | Reaction Co-efficient |
| RCE | Resonant Cavity Enhanced |
| RCF | Relative Centrifugal Force |
| RCNP | Research Center for Nuclear Physics |
| RCS | Real Compton Scattering |
| RCU | Rapid Cooling Unit |
| RCV | Reactor Control Volume |
| RD | Relative Dispersion |
| RDC | Reactor Dosimetry Center |