In Italian, the phrase a cappella means, literally, in the manner of chapel. Whoever coined the phrase presumably attended the type of church service in which people sing without musical accompaniment. In any case, without musical accompaniment is the primary definition of this loan phrase in English. It’s mainly an adjective and an adverb, but it also functions as a noun (e.g., she sang an a capella).
The phrase came to English around the 18th century. It originally applied only to choral music but was soon used to describe any type of singing without instrumental accompaniment,1 and that is its most commonly used sense today.
When a cappella was brought to English, it was commonly postpositive in the Italian manner. This means that it followed what it modified—e.g., the chorale a cappella was beautiful. But today the phrase is treated like any other English modifier, and it usually comes before what it describes—e.g., the a cappella chorale was beautiful.
A cappella is two words, and there are two p‘s and two l‘s. It’s commonly misspelled in several ways, including acapella and acappella. Though we’re italicizing it for the purposes of this post, a cappella is well established in English and does not need to be italicized in normal use.
Six a cappella works by living composers made up the concert’s first half. [Los Angeles Times]
The movie takes place in the competitive world of a cappella singing groups. [Independent]
The Madrigal Companie choir specialises in a cappella music of the Renaissance era. [Taranaki Daily News]
The rest of Krell’s new disc, which rolls through moments of quiet a cappella just as easily as swells of violin and static. [Globe and Mail]
The cast’s precision and passion in a cappella song and traditional dance was a treat to watch. [Independent Online]