| Term | Definition | Contributor | Modified |
|---|---|---|---|
| oligocene | No definition provided | Ryan McGranaghan | 2023.04.16 |
| Oligocene period | No definition provided | Christopher Rauch | 2023.12.01 |
| Oligochaeta | No definition provided | Christopher Rauch | 2023.12.01 |
| Oligoclase | No definition provided | Ryan McGranaghan | 2023.04.16 |
| Olive | No definition provided | Christopher Rauch | 2023.12.01 |
| Olive Branch (Ship) | No definition provided | Christopher Rauch | 2023.12.01 |
| Olive--Diseases and pests | No definition provided | Christopher Rauch | 2023.12.01 |
| Olivenite | No definition provided | Ryan McGranaghan | 2023.04.16 |
| Olive-oil | No definition provided | Christopher Rauch | 2023.12.01 |
| Oliver Cromwell (Privateer) | No definition provided | Christopher Rauch | 2023.12.01 |
| Olivin-diabase | No definition provided | Christopher Rauch | 2023.12.01 |
| Olivine | No definition provided | Ryan McGranaghan | 2023.04.16 |
| Olkhonskite | No definition provided | Ryan McGranaghan | 2023.04.16 |
| Olmiite | No definition provided | Ryan McGranaghan | 2023.04.16 |
| Olmsteadite | No definition provided | Ryan McGranaghan | 2023.04.16 |
| ols | No definition provided | Ryan McGranaghan | 2023.04.16 |
| Olsacherite | No definition provided | Ryan McGranaghan | 2023.04.16 |
| Olshanskyite | No definition provided | Ryan McGranaghan | 2023.04.16 |
| Oltenitza, Battle of, 1853 | No definition provided | Christopher Rauch | 2023.12.01 |
| Oltenitza. Battle of. 1853 | No definition provided | Christopher Rauch | 2023.12.01 |