a cappella

A cappella arrived in English from Italian sometime around the late-18th century. In Italian, a cappella means "in chapel or choir style." Cappella is the Italian word for "chapel"; the English word chapel is ultimately (if independently) derived from the Medieval Latin word cappella, which is the source of the Italian cappella as well. Scholars once thought all "chapel style" music written before the 1600s was performed a cappella, but modern research has revealed that instruments might have doubled or substituted for some voices back then. Today a cappella describes a purely vocal performance.