a cap·pel·la 
/ˌɑ:kəˈpɛlə, Brit ˌækæˈpɛlə/ adverb
/ˌɑ:kəˈpɛlə, Brit ˌækæˈpɛlə/ adverb : without instrumental music
▪ The choir sings a cappella.
▪ The choir sings a cappella.
— a cappella adjective
▪ a cappella singing/songs
▪ a cappella singing/songs
