This term was originally applied to almost any kind of concerted music for voices and instruments of the Baroque era. Today it is taken to mean a composition that shows off a specific instrument (or instruments) with the orchestra used as accompaniment.a piece of instrumental music that contrasts a solo instrument or a small group of solo instruments with the main body of the orchestra. in the earlier 17th century the word had a more general significance, but in the early 18th century it came to mean primarily a work as described above