• An anticipation (ANT) occurs when a note is played before the chord to which the note
belongs and resolves when the "anticipated" chord is reached:
• A neighbor tone (NT) or auxiliary note is a nonchord tone that passes from a chord tone
directly above or below it and resolves to the same tone:
In practice and analysis, neighboring tones are often differentiated depending upon whether or not they
are lower or higher than the chord tones surrounding them. A neighboring tone that is a step higher than
the surrounding chord tones is called an upper neighboring tone or an upper auxiliary note while a
neighboring tone that is a step lower than the surrounding chord tones is a lower neighboring tone or
lower auxiliary note.
As with above but on an accented beat.
As with above but on an accented beat.
Endeavor, moreover, to introduce suspensions now in this voice, now in that, for it is incredible how much grace the melody acquires by this means. And every note which has a special function is rendered audible thereby. —Johann Joseph Fux (1725), 
A suspension (SUS) (sometimes referred to as 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 are played again against the second chord (against which they are nonchord tones called the "Suspension") before resolving to a chord tone stepwise (the "Resolution"). Note that the whole process is called a suspension as well as the specific non-chord tone(s):
Suspension as an elided passing tone:
Suspensions may be further described using the number of the interval forming the suspension and its resolution; e.g. 4-3 suspension, 7-6 suspension, or 9-8 suspension. Suspensions resolve downwards; otherwise it is a retardation. A suspension must be prepared with the same note (in the same voice) using a chord tone in the preceding chord; otherwise it is an appoggiatura.
2-3 suspension in Lassus's Beatus vir in sapientia, mm.23-24
Decorated suspensions are common and consist of portamentos or double eighth notes, the second being a lower neighbor tone.
A chain of suspensions constitutes the fourth species of counterpoint; an example may be found in the second movement of Arcangelo Corelli's "Christmas Concerto".
• An appoggiatura (APP) is a type of accented incomplete neighbor tone approached skip-wise from one chord tone and resolved stepwise to another chord tone ("overshooting" the chord tone).
• A portamento is the late Renaissance precursor to the anticipation, though today it refers to a glissando.
• Nonharmonic bass notes are bass notes which are not a member of the chord below which they
are written. Examples include the Elektra chord.
Nonharmonic bass from Stravinsky's Symphony of Psalms 3rd mov.
• Changing tones (CT) are two successive nonharmonic tones. A chord tone steps to a nonchord
tone which skips to another nonchord tone which leads by step to a chord tone, often the same
chord tone. They may imply neighboring tones with a missing or implied note in the middle.
Also called double neighboring tones or neighbor group.
Another form of nonchord tone is a pedal point or pedal tone (PD) or note, almost always the tonic or
dominant, which is held through a series of chord changes. The pedal point is almost always in the
lowest voice (the term originates from organ playing), but it may be in an upper voice; then it may be
called an inverted pedal. It may also be between the upper and lower voices, in which case it is called
an internal pedal.
Chromatic nonharmonic tone
A chromatic nonharmonic tone is a nonharmonic tone that is chromatic, or outside of the key and creates half-step motion. The use of which, especially chromatic appoggiaturas and chromatic passing tones, increased in the Romantic Period.
Chromatic nonharmonic tones (in red) in Frédéric Chopin's op. 28, no. 21, mm. 1-4