Sinfonia (IPA: [simfoˈniːa]) is the Italian word for symphony, from the Latin symphonia, in turn derived from Ancient Greek συμφωνία symphōnia (agreement or concord of sound), from the prefix σύν (together) and ϕωνή (sound). In English it most commonly refers to a 17th- or 18th-century orchestral piece used as an introduction, interlude, or postlude to an opera, oratorio, cantata, or suite (Abate 1999, who gives the origin of the word as Italian). The word is also found in other Romance languages such as Spanish or Portuguese.
In the Middle Ages down to as late as 1588, it was also the Italian name for the hurdy-gurdy (Marcuse 1975, p. 477). Johann Sebastian Bach used the term for his keyboard compositions also known as Three-part Inventions, and after about 1800, the term, when in reference to opera, meant "Overture" (Fisher 1998, p. 386).
In the 20th and 21st centuries it is found in the names of some chamber orchestras, such as the Northern Sinfonia (Kennedy 2006).
Examples of such "sinfonias" composed after the classical era include: