| Abbreviation | Definition |
|---|---|
| OLAGA | Obesity Lifestyle and Genetic Adaptations |
| OMIM | Online Mendelian Inheritance in Man |
| OMIN | Online Mendelian Inheritance in Man |
| OMP | Outer Membrane Protein |
| OPHG | Office of Population Health Genomics |
| OPRR | Office of Protection from Res. Risks |
| ORA | Outer Rhabdomeres Absent |
| ORAU | Oak Ridge Associated Universities |
| ORC | Origin Recognition Complex |
| ORDA | NIH Office of Recombinant DNA Activities |
| ORF | Open Reading Frame |
| ORF | Open Reading Frames in DNA sequences |
| ORISE | Oak Ridge Institute for Science and Education |
| OS | Opposite Strand |
| OSE | Oryza Sativa Embryo |
| OSE | Oryza Sativa Embryogenesis |
| OSP | Outer Surface Protein |
| OSPA | Outer Surface Protein A |
| OTA | Office of Technology Assessment |
| OXL | L-4-Oxalysine |