Tonality

In music theory, the tonality of a piece is its perceived key or mode. Tonality centers around a tonic note and chord, where the piece is most stable, and may be indicated by clues such as a key signature or the function of the piece's chords. For example, in the key of C major, the tonic note is C, and the tonic triad is C major (consisting of notes C, E and G). Similarly, in B Lydian, the tonic note is B, and the tonic triad is B major (consisting of notes B, D# and F#). Simple folk songs, orchestral pieces, and pop songs often start and end with the tonic note. In such pieces, cadences in which the dominant chord or dominant seventh chord resolves to the tonic chord often play an important role in establishing tonality. Harmony in jazz similarly includes certain tonal characteristics of the European common practice period (colloquially known as "classical music"), although not all. Modernistic music, by contrast, was often atonal.