A Dictionary of Music and Musicians/Grosso
GROSSO. Italian for 'great.' The 'Concerto Grosso' of the first half of the 18th century, said to have been invented by Torelli in 1709, was a piece for a combination of several solo instruments with the full band. Thus Corelli's Concerti Grossi (op. 6) are described in the title as 'con due violini e violoncello di concertino obligati, e due altri violini e basso di concerto grosso, ad arbitrio che si potramo radoppiare.' The same is the case with Handel's '12 Grand Concertos,' which are for 2 solo violins and a cello, accompanied by and alternating with a band of 2 violins, viola, cello, and bass. The piece contained 4, 5, or 6 movements of different tempo, one being usually a fugue and one a dance, and all in the same key.
The name does not occur in the works of either Haydn or Mozart. It was probably last used by Geminiani, who, before his death in 1761, arranged Corelli's solos as Concerti Grossi.[ G. ]