jazz choir

a group of singers who sing jazz songs. It can be accompanied by a combo (just piano, bass, and drums; or a full out mini big band) or completely a capella (sometimes with a vocal percussionist). Either way it is performed is fine, as long as jazz tunes or arrangments are being chosen to perform. There is can be a very thin line between being a pop choir and a jazz choir.

"That jazz choir was swinging!"
"'That jazz choir did awesome singing that Michael Jackson set!'
'No, that wasn't a jazz choir. That would be called a pop choir.'
Oh, my bad. They should try singing "Swing, Swing, Swing." They'd sound awesome'"