Sentence:  Truman's total vote was 24,104,836. Dewey received 21,969,500;.... Truman won by a <WSD>plurality</WSD> of 2,135,336, but it was the first time since 1916 that a winner has failed to capture a majority of all votes cast. 
Meaning of the word marked with <WSD> tags:  A margin by which a number exceeds another number, especially of votes.