Sentence:  When the <WSD>Korean</WSD> war began , on June 25 , 1950 , the anniversary of the day Custer had gone down fighting at the Little Big Horn and the day the regiment had assaulted the beachhead of Leyte during World War 2 , , the 7 th Cavalry was not in the best fighting condition . 
Meaning of the word marked with <WSD> tags:  a war between North and South Korea; South Korea was aided by the United States and other members of the United Nations; 1950-1953