concerto grosso (It.). Great concerto. Early form of concerto at its zenith in the 17th and 18th cents., though the term has been used by 20th-cent. composers, e.g. Bloch and Vaughan Williams, for works based on earlier models. The works were antiphonal, i.e. a small body of str. (concertino, concertato, or concertante) was heard in alternation, contrast and combination with a larger group (ripieno). These were in several movts., roughly similar to the 18th-cent. ov. or suite. The most celebrated early concerti grossi are those by Corelli (1712) (Concerti grossi con duoi violini e violoncello di concertino obbligati) and those by Handel (1739). J. S. Bach's Brandenburg Concertos Nos. 2, 4, 5, and 6 are traditional concerti grossi.