Sounding alone; unisonous.In music, sounded simultaneously; specifically, noting two or more voice-parts that are coincident in pitch, or a passage or effect thus produced.n. In music: The interval, melodic or harmonic, between any tone and a tone of exactly the same pitch; a perfect prime, acoustically represented by the ratio 1:1. The term is also used as a synonym of prime (as, an augmented unison), though this is objectionable.n. The interval of the octave, especially when occurring between male and female voices, or between higher and lower instruments of the same class.n. The state of sounding at the same pitch—that is, of being at the interval of a unison.n. A single unvaried tone; a monotone. Same as unison string.n. Accordance; agreement; harmony; concord.