The term 'MARCH GREAT' is a crossword solution that can be filled in with the word 'SOUSA, ' which is a five-letter word. John Philip Sousa was an American composer and conductor of the late Romantic era, known particularly for American military marches. He is known as 'The March King' or the 'American March King' due to his mastery of the march form. He composed over 130 marches during his lifetime, including 'The Stars and Stripes Forever, ' which is widely considered to be the National March of the United States.