Unison

(Synop., § 130), n. [L. Lat. unisonus, from Lat. unus, one, and sonus, a sound; Fr. unisson, Sp. unison, It. *unisono.] 1. Harmony; agreement; concord; union. Unison is the word which at once characterizes true religion, and describes the upper world. Bp. Taylor. 2. (Mus.) An accordance or coincidence of sounds proceeding from an equality in the number of vibrations made in a given time by a sonorous body. ☞ If two cords of the same substance have equal length, thickness, and tension, they are said to be in unison, and their sounds will be in unison. Sounds of very different qualities and force may be in unison, as the sound of a bell may be in unison with a sound of a flute. Unison, then, consists in sameness of degree, or similarity in respect to gravity or acuteness, and is applicable to any sound, whether of instruments or of the human organs, &c. A piece or passage is said to be sung or played in unison when all the voices or instruments perform the same part, in which sense unison is contradistinguished from harmony. 3. A single, unvaried tone. [Rare.] Pope. In unison, in agreement; in harmony.