In music, a consonance (Latin com-, "with" + sonare, "to sound") is a harmony, chord, or interval considered stable, as opposed to a dissonance (Latin dis-, "apart" + sonare, "to sound"), which is considered to be unstable (or temporary, transitional). In more general usage, a consonance is a combination of notes that sound pleasant to most people when played at the same time; dissonance is a combination of notes that sound harsh or unpleasant to most people.
Consonance has been defined variously through:With ratios of lower simple numbers being more consonant than those that are higher (Pythagoras). Many of these definitions do not require exact integer tunings, only approximation.
Coincidence of partials: with consonance being a greater coincidence of partial (called harmonics or overtones when occurring in harmonic timbres) (Helmholtz, 1877/1954). By this definition, consonance is dependent not only on the width of the interval between two notes (i.e., the musical tuning), but also on the combined spectral distribution and thus sound quality (i.e., the timbre) of the notes (see the entry under critical band). Thus, a note and the note one octave higher are highly consonant because the partials of the higher note are also partials of the lower note. Although Helmholtz's work focused almost exclusively on harmonic timbres and tunings, subsequent work has generalized his findings to embrace......