WordNet (r) 3.0 (2006):

United States
    n 1: North American republic containing 50 states - 48
         conterminous states in North America plus Alaska in
         northwest North America and the Hawaiian Islands in the
         Pacific Ocean; achieved independence in 1776 [syn: United
         States, United States of America, America, the
         States, US, U.S., USA, U.S.A.]
    2: the executive and legislative and judicial branches of the
       federal government of the United States [syn: United States
       government, United States, U.S. government, US
       Government, U.S.]