unisonn.[LL. unisonus having the same sound; L. unus one + sonus a sound: cf. F. unisson, It. unisono. See One, and Sound a noise.]1. Harmony; agreement; concord; union.()2. (Mus.) Identity in pitch; coincidence of sounds proceeding from an equality in the number of vibrations made in a given time by two or more sonorous bodies. Parts played or sung in octaves are also said to be in unison, or in octaves.()()3. A single, unvaried.(Pope.)In unison, in agreement; agreeing in tone; in concord.()a.[Cf. It. unisono. See Unison, n.]1. Sounding alone.()[sounds] intermixed with voice,
Choral or unison. (Milton.)2. (Mus.) Sounded alike in pitch; unisonant; unisonous; as, unison passages, in which two or more parts unite in coincident sound.()