Nonchord tone

A nonchord tone (NCT), also known as a nonharmonic or embellishing tone, is a note in a piece of music that does not belong to the chord implied or expressed by the harmonic framework. Chord tones, by contrast, are notes that form part of the functional chord. While this concept is most frequently applied to the common practice period of classical music, it can also be used to analyze other tonal music, such as Western popular music.

Nonchord tones are often grouped into accented and unaccented types, depending on whether the dissonance falls on a strong or weak beat (or part of a beat). Over time, some musical styles adopted chord types outside the common-practice style, where notes that would typically be nonchord tones are instead treated as chord tones—for example, the seventh of a minor seventh chord. In 1940s-era bebop jazz, an F♯ played with a C7 chord would be considered a chord tone if the chord were analyzed as C7(♯11). In European classical music, the increasing use of dissonance over time, driven by the interplay of linear and vertical forces, gradually normalized ninth, eleventh, and thirteenth chords in analysis and theory; each additional nonchord tone above the basic triad became absorbed into the chord itself.

Chord and nonchord tones are defined by whether they belong to a chord: pitches that make up a chord are chord tones, and any other pitches are nonchord tones. They are also defined by when they sound: nonharmonic tones are pitches that sound with a chord but are not part of it. For instance, in a passage implying a C-major chord, the notes C, E, and G are chord tones, while any other note played at that time—such as F♯—is a nonchord tone. These tones are most obvious in homophonic music but occur at least as often in contrapuntal music.

Most nonharmonic tones are dissonant, creating intervals of a second, fourth, or seventh, and conventionally resolve to a chord tone. If the note does not resolve until the next harmony change, it may instead form a seventh chord or extended chord. Theoretically, in a three-note chord, there are nine possible nonchord tones in equal temperament, but in practice they usually fall within the prevailing key. Augmented and diminished intervals are also considered dissonant, and all nonharmonic tones are measured from the bass note, except in the case of nonharmonic bass tones.

Nonharmonic tones typically appear in a pattern of three pitches, with the nonharmonic tone in the middle. They are categorized by how they are used, with the key distinction being whether they occur on a strong or weak beat (accented or unaccented). They are also distinguished by their direction of approach and departure, the voice or voices in which they occur, and the number of notes they contain.

**Unaccented**

*Anticipation*: An anticipation (ANT) occurs when a note is approached by step and then remains the same—essentially a note of the second chord played early. In the example, the dissonant B in bar 1 is approached by step and resolves when that same pitch becomes a chord tone in bar 2. A portamento is the late Renaissance precursor to the anticipation, though today it refers to a glissando.

*Neighbor tone*: A neighbor tone (NT) or auxiliary note (AUX) is a nonchord tone that passes stepwise from a chord tone directly above or below it (often creating dissonance) and resolves to the same chord tone. In practice, neighboring tones are sometimes differentiated as upper (a step higher) or lower (a step lower) than the surrounding chord tones. Following Heinrich Schenker’s usage in *Free Composition*, some authors reserve the term "neighbor note" for the lower neighbor a half step below the main note. The German term *Nebennote* is a broader category, including all nonchord tones approached from the main note by step.

*Escape tone*: An escape tone (ET) or *echappée* is a type of unaccented incomplete neighbor tone approached stepwise from a chord tone and resolved by a skip in the opposite direction back to the harmony.

*Passing tone*: A passing tone (PT) or passing note is a nonchord tone prepared by a chord tone a step above or below it and resolved by continuing in the same direction stepwise to the next chord tone (which may be part of the same chord or the next chord in the progression). Where two nonchord tones occur before the resolution, they are called double passing tones or double passing notes.

**Accented non-chord tones**

*Passing tone*: A tone that sits between two chord tones and is between them.

*Neighbor tone*: A neighbor tone involves a step up or down from a note (or chord tone) and then a return to the original note.

*Suspension and retardation*: A suspension (SUS), sometimes called a syncope, occurs when the harmony shifts from one chord to another, but one or more notes of the first chord (the preparation) are either temporarily held over into or played again against the following chord.