antiphon

Etymology

From French antiphone or Medieval Latin antiphōna, from Ancient Greek ἀντίφωνα (antíphōna, “responses, musical accords”), neuter plural substantive of ἀντίφωνος (antíphōnos, “concordant”) from ἀντί (antí, “in return”) + φωνή (phōnḗ, “sound”). Doublet of anthem.

noun

1. A devotional chant; a piece of music sung responsively.
   Father Vaillant came back in his vestments, with his pyx and basin of holy water, and began sprinkling the bed and the watchers, repeating the antiphon, Asperges me, Domine, hyssopo, et mundabor. 1927, Willa Cather, Death Comes for the Archbishop, Book V, section 2, page 171-172
2. A response or reply.
   The Clown […] says: ‘And so we wept; and there was the first gentleman-like tears that ever we shed’; to which his father, the Shepherd, adds the comfortable antiphon, ‘We may live, son, to shed many more.’ 2007, Barbara Everett, “Making and Breaking in Shakespeare's Romances”, in London Review of Books, 29:6, page 20