re·spon·so·ry /rɪˈspɒnsəri/

–noun, plural -ries. Ecclesiastical .
an anthem sung after a lection by a soloist and choir alternately.

1375–1425; late ME < LL respōnsōrium, equiv. to L respond ( ēre ) to respond + –tōrium -tory2 , with dt > s


But after the responsory, the hymn, and the versicle, as the chanting of the Gospel began, I glimpsed just above the altar, beyond the windows of the choir, a pale glow that was already making the panes shine in their various colors, subdued till then by the darkness.

Source: The Name of the Rose by Umberto Eco.