Nonchord tone

A nonchord tone is a tone in a piece of homophonic music which is not in the chord that is formed by the other tones playing. For example, if a piece of music is currently on a C Major chord, the notes CEG form the chord, while any other note played at that time is a nonchord tone. Since nonchord tones are dissonances, in common practice they are allowed only as suspensionss, anticipations, passing tones, and upper and lower neighbor tones which then resolve.

• An anticipation occurs when a note is played before the chord to which the note belongs to.
• A neighbor tone or auxilliary note is a nonchord tone which is preceded by a chord tone directly above or below it and followed by the same tone.
• A passing tone or passing note is the nonchord tone of a part which had started at one chord tone and moved up or down through one (or more) nonchord tone and ending on another chord tone.
• A suspension occurs when the harmony shifts from one chord to another, but one or more notes of the first chord are held over into the second in which they are nonchord tones, usually temporarily. For an audiovisual illustration of the concept of harmonic suspension, visit external link suspension and pedal point.

While it is theoretically possible that for a three note chord in twelve tone equal temperament there are nine possible nonchord tones, nonchord tones are usually still in the key of the piece being played, having more than one nonchord tone quickly blurs their status as nonchord tones, and they must be used sparsely enough not to be felt as an added tone, a tone added to and therefor a part of the chord.