| Abbreviation | Definition |
|---|---|
| ODEND | Optical Detected Electron Nuclear Double Resonance |
| ODEPR | Optical Detected Electron Paramagnetic Resonance |
| ODRS | Orbital Decay and Reboost Simulation |
| ODS | Optimized Deformation System |
| OFR | Optics For Research |
| OG | Orientation Group |
| OGB | Original Grain Boundary |
| OH | Odd Harmonics |
| OHEP | Office of High Energy Physics |
| OHTL | Over Head Transmission Line |
| OIAP | Obukhov Institute of Atmospheric Physics |
| OITD | Overlap Induced Ternary Dipole |
| OJM | Open Journal of Microphysics |
| OKC | Open Kinetic Chain |
| OLED | organic light-emitting diode |
| OMPC | Ohio Medical Physics Consulting |
| OMPI | Ottawa Medical Physics Institute |
| OOCA | Object Oriented Computing in Astrophysics |
| OOMPAA | Object-Oriented Model for Probing Assemblages of Atoms (physics) |
| OOS | Optics Online Store |