Encyclopedias, Almanacs, Transcripts, and Maps
- ultra high frequency
- Um?pati ?iv?c?rya
- Umai
- umbrella bird
- Ummah
- UN
- Unarius Academy of Science
- Uncertainty in Science, Statistics
- underground railway
- Underhill, Evelyn
- Ungarinyin Religion
- Ungulate Domestication
- Uniate Churches
- unified field theory
- Union of Concerned Scientists
- unit trust
- Unitarian Universalist Association
- United Kingdom
- United Nations agencies
- United Nations Commission on Sustainable Development