Sentence:  However , if their <WSD>United</WSD> States income is not subject to the withholding of tax on wages , their returns are due June 15 , 1962 , if they use a calendar year , or the 15 th day of the 6 th month after the close of their fiscal year . 
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