Sentence:  The Serge Prokofieff whom we knew in the <WSD>United</WSD> States of America was gay , witty , mercurial , full of pranks and bonheur - and very capable as a professional musician . 
Meaning of the word marked with <WSD> tags:  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