Main Entry: bugle
        Function: noun
        Etymology: Middle English, buffalo, instrument made of buffalo horn, bugle, from Middle French, from Latin buculus, diminutive of bos head of cattle -- more at COW
        Date: 14th century
        : a valveless brass instrument that resembles a trumpet and is used especially for military calls

     Walt Whitman uses the word "bugle" to show the celebration the people feel for President Abraham Lincoln.  Once Lincoln delivers America from the devastation of war, the people love and rejoice in what he (as well as many Americans) had accomplished.  So Whitman enters the the symbolism of a "bugle" to show how the people celebrate.
 
 

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