Sentence:  Meager and shabby by-products linger to haunt our memories of a once mighty protagonist ; a maladroit reharmonization of our National Anthem ( The Star-Spangled Banner ) ; a poor attempt to write an idiomatic jazz <WSD>concerto</WSD> ; a circus polka for elephants ; his hopes that the tunes from his old music might be used for popular American commercial songs ! 
Meaning of the word marked with <WSD> tags:  a composition for orchestra and a soloist