I. adverb
also a ca·pel·la ˌäkəˈpelə, ˌȧ-
Etymology: Italian a cappella in chapel or choir style
1. : in a style marked by the absence of instrumental accompaniment
sing a cappella
2. obsolete : in alla breve time
II. adjective
also a capella | ̷ ̷ ̷ ̷| ̷ ̷ ̷ ̷
1. : unaccompanied by instruments : marked by or specializing in unaccompanied singing
an a cappella choir
2. obsolete : alla breve