Tonality refers to the overall harmonic content of a work. It exists on two levels. The first is the overall tonality of a piece or section of that piece. The second is the harmonic content at any given moment in the piece. Tonality is often defined by the key within which the music is set. Usually that key suggests either a major tonality or a minor tonality. Four other terms associated with tonality are chords, dissonance, consonance, atonal, and harmonic progression.