a capellayoudaoicibaDictYouDict[a capella 词源字典]
1876, earlier alla capella (1847), from Italian, "in the manner of the chapel," literally "according to the chapel," from cappella "chapel" (see chapel). Originally in reference to older church music (pre-1600) which was written for unaccompanied voices; applied 20c. to unaccompanied vocal music generally.[a capella etymology, a capella origin, 英语词源]