Encyclopedias, Almanacs, Transcripts, and Maps
- unit trust
- Unitarian Universalist Association
- United Kingdom
- United Nations agencies
- United Nations Commission on Sustainable Development
- United Nations Conference on the Human Environment (1972)
- United Nations Division for Sustainable Development
- United Nations Earth Summit (1992)
- United Nations Environment Programme
- United Nations peace-keeping force
- United States of America
- United States Weather in Atlas Format
- units
- Units of Energy
- Unkulunkulu
- unnilquadium
- unsaturated compound
- Untouchables, Religions of
- Upaniṣads
- Upāya