Source : Webster's Revised Unabridged Dictionary (1913)

Antiphonal \An*tiph"o*nal\, a.
   Of or pertaining to antiphony, or alternate singing; sung
   alternately by a divided choir or opposite choirs. --Wheatly.
   -- {An*tiph"o*nal*ly}, adv.

Antiphonal \An*tiph"o*nal\, n.
   A book of antiphons or anthems.

Source : WordNet®

antiphonal
     adj 1: containing or using responses or antiphons recited or sung
            in alternation; "responsive reading"; "antiphonal
            liturgy" [syn: {responsive}]
     2: relating to or resembling an antiphon [syn: {antiphonary}]
     n : bound collection of antiphons [syn: {antiphonary}]