A Bureau of the Census determination of a central place (or places) and the adjacent densely settled surrounding territory that together have a minimum residential population of 50,000 people and a minimum average density of 1,000 people/square mile. This is a simplified definition of a UA, the full definition is very complex.
URBANIZED AREA (UA
Meaning of URBANIZED AREA (UA in English
Environmental engineering English vocabulary. Английский словарь экологического инжиниринга. 2012