Notable next-door neighbors
Many music theory textbooks illustrate melodies that often consist, in part, of chord tones—the notes that match an underlying harmonic progression. An example of this may be seen below, in the folk song Black is the Color of My True Love's Hair. The first three pitches, above the words "Black, black, black," are chord tones outlining a D minor triad. The three pitches that correspond to "true love's hair" outline an A minor triad.
Several theory texts, including the one I use in my Fundamentals of Music classes at Pace University, ask students to begin composing short melodies using only the notes of various major and minor triads. This is an effective way for students to develop familiarity with chord tones.
Melodies that consist exclusively of the tones of major and minor triads, however, are not only rare, but, as one can imagine, potentially boring. In order to generate greater listener interest, composers and improvisers almost always include pitches that lie outside the harmony. These are called non-chord or non-harmonic tones. These terms should not imply or suggest that the tones do not sound good. On the contrary, the way chord tones and non-chord tones interact with one another is a significant, even crucial, feature of tonal music.
There are several types of non-chord or non-harmonic tones, including:
1) Lower neighbors
2) Upper neighbors
3) Passing tones
4) Escape tones (échappées)
7) Anticipation tones
A lower neighbor is a non-chord tone that departs from a chord tone downward by a whole or half step (major or minor 2nd). It then immediately returns up to the same chord tone.
An upper neighbor is a non-chord tone that departs from a chord tone upward by a whole or half step, immediately returning down to the same chord tone.
A passing tone is a non-chord tone that moves stepwise in the same direction between one chord tone and another.
Exercise in non-harmonic tone identification
For practice identifying non-chord tones, identify each of the pitches marked with an x below as a lower neighbor, upper neighbor, or passing tone.
Escape tone (échappée)
An escape tone or échappée (pronounced "ay-sha-PAY") is a stepwise note placed between two adjacent scale tones. The motion of the escape tone is contrary to the motion of the scale tones.
A cambiata is a stepwise note placed between two scale tones that moves in the same direction as the scale tones.
Traditionally, a suspension occurs when one or more notes of a chord are held over or played against a second chord before resolving in a stepwise motion to a chord tone. A suspension in jazz can have a slightly different meaning (for a detailed discussion of this see my article "Jazz suspensions: Bridges to somewhere" in the March/April 2009 issue of Clavier Companion).
An anticipation tone is a note that is a chord tone of an upcoming chord. It is played in advance of that chord, and then resolves when the chord is played.
A very effective application of non-harmonic tones, especially in jazz, is the employment of two neighbors: the upper and lower neighbors played (in either order) just prior to the upcoming target. Jazz musicians often refer to these neighbors as approach tones and to the resolution note as a target tone.
Non-harmonic tones should be an essential part of the vocabulary of every composer and improviser. An understanding and mastery of these materials will go a long way towards the creation of music that will be of special and enduring interest to listeners.
Excellent definitions and examples of many of the above terms can be found in The FJH Classic Music Dictionary, 2nd Edition, by Edwin McLean.