| Term | Definition | Contributor | Modified |
|---|---|---|---|
| Pentahydrite | No definition provided | Ryan McGranaghan | 2023.04.16 |
| Pentahydroborite | No definition provided | Ryan McGranaghan | 2023.04.16 |
| Pentastomida | No definition provided | Christopher Rauch | 2023.12.01 |
| Pentateuch | No definition provided | Christopher Rauch | 2023.12.01 |
| Pentlandite | No definition provided | Ryan McGranaghan | 2023.04.16 |
| Pentoses | No definition provided | Christopher Rauch | 2023.12.01 |
| penumbra | The outer, lighter portion of a sunspot. This structure has a striated or filamented appearance | Ryan McGranaghan | 2023.04.16 |
| penumbra | The sunspot area that may surround the darker umbra or umbrae. In its mature form it consists of linear bright and dark elements radial from the sunspot umbra. | Ryan McGranaghan | 2023.04.16 |
| penumbra | No definition provided | Ryan McGranaghan | 2023.04.16 |
| Penumbra | The portion of a shadow in which light from an extended source is partially but not completely cut off by an intervening body; the area of partial shadow surrounding the umbra. The lighter part of a shadow during an eclipse. An observer standing in the penumbra of a Solar eclipse will see a partial eclipse. | Ryan McGranaghan | 2023.04.16 |
| Penwithite | No definition provided | Ryan McGranaghan | 2023.04.16 |
| Penzhinite | No definition provided | Ryan McGranaghan | 2023.04.16 |
| Peonage | No definition provided | Christopher Rauch | 2023.12.01 |
| Peony | No definition provided | Christopher Rauch | 2023.12.01 |
| People’s party | No definition provided | Christopher Rauch | 2023.12.01 |
| Pepin, Donation of | No definition provided | Christopher Rauch | 2023.12.01 |
| Pepper | No definition provided | Christopher Rauch | 2023.12.01 |
| Pepper-weevil | No definition provided | Christopher Rauch | 2023.12.01 |
| Peprossiite (Ce) | No definition provided | Ryan McGranaghan | 2023.04.16 |
| Pepsin | No definition provided | Christopher Rauch | 2023.12.01 |