U

unified settlement system ( edinaia sistema rasseleniia[ESR]) The analytical construct used by many Soviet geographers to describe the national integrated hierarchy of urban centers throughout the Soviet Union.

union republic (soiuznaia respublika) The largest and most important nationality-based administrative subdivision of the USSR. All 15 union soviet socialist republics have an international boundary and share a theoretical right of secession from the USSR.

union-republic ministry The agency of the USSR Council of Ministers responsible for coordinating the work of ministries of the same name and similar purpose operating within each of the Soviet Union's 15 republics, usually in a given economic sector, such as the Ministry of the Food Industry, the Ministry of Health, and the Ministry of Foreign Affairs.

urban district or ward ( gorodskii raion) The lowest-level urban administrative and political subdivision in the Soviet state system.