Many melodies utilize temporary dissonances, or nonharmonic tones, which fall outside of the existing harmony. (These are sometimes referred to as non-chord tones.) As such, they are dissonances that need to be prepared and resolved.

There are only a few acceptable nonharmonic tones and each has a specific way of approaching and leaving the tone.

Passing Tone

The passing tone (PT) is approached and left by step, and connects two different chord tones, either within the same chord or between two different chords. A passing tone can be accented (when it falls on a strong beat) or unaccented (when it falls on a weak beat). Larger intervals can be filled in with a series of diatonic or chromatic passing tones.

Diatonic

Chromatic

neighbor tone and neighboring group

The neighbor tone (NT) moves from a chord tone to a nonharmonic tone a step above or below and then returns to the same chord tone. A neighbor tone can be accented or unaccented.

The neighboring group (called a cambiata or changing tones) embellishes a chord tone with nonharmonic tones a step below and a step above diatonically or chromatically.

escape tone

The escape tone (ET) is approached by step and left by skip in the opposite direction. It always falls on a weak unaccented beat.

anticipation

The anticipation (ant.) anticipates a chord tone, often at a cadence. It is unaccented and always has a shorter rhythmic value than the note it anticipates.

pedal point

The pedal point is a prolonged tonic or dominant bass note that is held beneath two or more unrelated chords. The last chord resolves properly. The device is a prolonged embellishment of the harmony established by the pedal, and the chords on top often sound like sets of simultaneous nonharmonic tones.

Suspension

The suspension (sus) is a chord tone that is delayed into the next harmony, creating a dissonance typically resolving down by step. It is accented, falling on a strong beat in relation to the chord of resolution. The three elements of a suspension are the preparation (P), suspension (S), and resolution (R). Suspensions can be tied over or accented without the tie. In figured bass, suspensions are labeled by the interval created above the bass. Possible suspensions are 9-8 (2-1), 7-6, 6-5, and 4-3.

Examples of 4-3, 6-5, and 9-8 suspensions:

The first example below shows a chain of 7-6 suspensions as part of a sequence. A combination of suspensions (such as 9-8 and 4-3) is also possible.

An upward resolving suspension is a retardation (ret): V⁽⁷⁾ – I^7-8. The 2-3 suspension is less common and occurs in the bass.

Use of the various types of suspensions:

appoggiatura

The appoggiatura (app) or leaning tone is an accented nonharmonic tone that is approached by skip and resolved by step. The tone “leans” (from It. Appoggiare, to lean) usually down (less often up) to its resolution. Heavily accented passing tones, neighboring tones, and suspensions may also qualify as appoggiaturas.

A special case is the incomplete neighbor tone (INT), which is a weak appoggiatura. It is unaccented, approached by skip and left by step, usually in the opposite direction, although resolution in the same direction is possible (measure 3).

Summary

1. The passing tone is approached and left by step in the same direction. The neighbor tone is left by step and returns by step to the original note.
2. The suspension is a chord tone that is delayed into the next harmony. The anticipation is a chord tone that is anticipated into the previous harmony.
3. The appoggiatura is approached by skip and resolved by step in the opposite direction. The escape tone is approached by step and left by skip in the opposite direction.