| Term | Definition | Contributor | Modified |
|---|---|---|---|
| Ungulata, Fossil | No definition provided | Christopher Rauch | 2023.12.01 |
| Ungursaite | No definition provided | Ryan McGranaghan | 2023.04.16 |
| Unicellular organisms | No definition provided | Christopher Rauch | 2023.12.01 |
| Unicode | Text in multi-byte Unicode format. | Ryan McGranaghan | 2023.04.16 |
| uniform flow | a wind flow where the velocity is not a function of position but is equal throughout | Fred Haan | 2023.03.27 |
| Uniforms | No definition provided | Christopher Rauch | 2023.12.01 |
| Uniforms, Civil | No definition provided | Christopher Rauch | 2023.12.01 |
| Uniforms, Military | No definition provided | Christopher Rauch | 2023.12.01 |
| Uniforms, Papal | No definition provided | Christopher Rauch | 2023.12.01 |
| uninterrupted | No definition provided | Ryan McGranaghan | 2023.04.16 |
| Union jack | No definition provided | Christopher Rauch | 2023.12.01 |
| Union label | No definition provided | Christopher Rauch | 2023.12.01 |
| Unions, Trade | No definition provided | Christopher Rauch | 2023.12.01 |
| unipolar magnetic region | A large-scale photospheric region where the magnetic elements are predominantly of one polarity (for example, the solar polar regions) | Ryan McGranaghan | 2023.04.16 |
| Unipolar Magnetic Region | No definition provided | Ryan McGranaghan | 2023.04.16 |
| unique | No definition provided | Ryan McGranaghan | 2023.04.16 |
| unit | No definition provided | Ryan McGranaghan | 2023.04.16 |
| Uni-tarianism | No definition provided | Christopher Rauch | 2023.12.01 |
| Unitarianism | No definition provided | Christopher Rauch | 2023.12.01 |
| Unitarianism--Doctrinal and controversial works | No definition provided | Christopher Rauch | 2023.12.01 |