Sentence:  The evidence suggests that foreign peoples believe the United States is weaker than the <WSD>Soviet</WSD> Union , and is bound to fall still further behind in the years ahead . 
Meaning of the word marked with <WSD> tags:  a former communist country in eastern Europe and northern Asia; established in 1922; included Russia and 14 other soviet socialist republics (Ukraine and Byelorussia and others); officially dissolved 31 December 1991