| Abbreviation | Definition |
|---|---|
| RHF | Restricted Hartree Fock |
| RHIC | Relativistic Heavy Ion Collider |
| RHIP | Relativistic Heavy Ion Physics |
| RHM | Roentgen Hour Meter |
| RHR | Right Hand Rule |
| RIBD | Reactive Ion Beam Deposition |
| RIBF | Radioactive Isotope Beam Factory |
| RIBG | Relativistic Ideal Bose Gas |
| RIBM | Resistive-Inertia Ballooning Mode |
| RICAP | Roma International Conference on Astroparticle Physics |
| RICC | Resistor Inductor Capacitor Circuit |
| RICE | Radio Ice Cerenkov Experiment |
| RIDIC | Radiation Internal Dose Information Center |
| RINF | Retinoid Inducible Nuclear Factor |
| RITA | Re-Invented Triple Axis |
| RIU | Refractive Index Unit |
| RIXS | Resonant Inelastic X-ray Scattering |
| RKB | Restricted Kinetic Balance |
| RKE | Rotational Kinetic Energy |
| RL | Relative Length |