A Dictionary of Music and Musicians/Invention
INVENTION. A term used by J. S. Bach, and probably by him only, for small pianoforte pieces—15 in 2 parts and 15 in 3 parts—each developing a single idea, and in some measure answering to the Impromptu of a later day. [App. p.685 "Only the first set of pieces mentioned, viz. the 15 in 2 parts, are called by this name; the 3-part compositions are called 'Sinfonien.'"] [G.]