DIATONIC- When a triad, chord or melody consists of notes solely from the given key, it is considered to be DIATONIC.

CHROMATIC- When a triad, chord or melody consists of notes from outside the given key, it is considered to be CHROMATIC.

NONESSENTIAL CHROMATICISM- This refers to non chord tones that are within the scale of a passage of music. They likely appear in between strong beats, while one chord tone moves to another.

ESSENTIAL CHROMATICISM- This refers to non chord tones that are from outside the scale of a passage of music. These can be considered a part of the chord its self.

TERTIAN HARMONIES- Harmonies created by the stacking of thirds.

EXTENDED CHORDS- In these chords, a non chord tone is added to a full 7th chord. It's should be noted that the 7th is necessary for a chord to be considered an extended chord.

SUSPENSIONS ("SUS" CHORDS)- In "classical theory", a note from the previous chord remains while all the others move to the following chord. Then it is resolved DOWN BY STEP on a weak beat of the new chord. In popular and jazz music, this is when a non chord tone replaces a chord tone (often the 2nd, 4th or 6th replacing 3rd or 5th).

"ADD" CHORDS- In these chords, a non chord tone is added to a full triad. SUBSTITUTIONS- As it relates to harmonies, one chord tone is omitted and replaced by a non-chord tone.

ALTERED CHORDS ("ALT" CHORDS)- In these chords the extended non chord tone is altered by either raising it (#) or lowering it (b). The 7th is still required to be present.

COMMON TONE DIMINISHED CHORDS (CT°)- In this case, a diminished chord shares a common tone with an adjacent chord.

LINEAR CHROMATIC- This is the idea that sometimes harmonies, beyond traditional function, occur as the result of chromatically ascending or descending lines. APPOGGIATURA CHORD- In this case, a note leaps from a chord tone to a non chord tone and then steps back down to a chord tone in the following chord.

SIMULTANEITY- This when a chord appears to have no function or explanation.

-In previous discussions, we saw the extended harmonies (i.e. 9th, 11th and 13th chords) occurring mainly on the DOMINANT (V) chord. In the 19th and 20th centuries, we will begin to see these harmonies occurring in other chords.

-In measure 2, below, we see the ii chord with an added 9th. Notice it still functions as a predominant, moving to V.

-Even though, this is an inversion, we will just call it ii9.

-The COMMON TONE DIMINISHED 7th chord can embellish any triad or V7 chord. But it typically embellishes I in major or V7 in major or minor.

-In this case, the chord moves from a I chord (C major) to a CTº7 (Cº7), who’s root shares a COMMON TONE with that I chord, and back to the I chord (C major) again.

-Because there is no theoretical root, this is displayed in our analysis as CTº7.

-In LINEAR CHROMATICISM, the harmonies are a result of chromatic ascending or descending lines. They may or may not fit into the functions we try to assign them in tonal music.

-Below, we see the Em chord in the bass holding steady, in measures 1 and 2. Meanwhile, the two higher voice are moving by half step in parallel motion on top of all this. The odd harmonies that occur from this could be simply explained as LINEAR CHROMATICM to avoid an otherwise cumbersome analysis.

-The appoggiatura is a non chord tone (NTC) approached by leap and left by a step.

-Appoggiaturas can create momentary, linear non functional sonorities.

-Appoggiatura chords are usually placed on downbeats, but not always!

-Below we see the D note in measure 1 leap up to the A note in the following measure while the G major chord holds the other voices in place. Finally, in measure 3, this voice steps back down to the G note of the C major chord. Notice the chord in measure 2 has been labeled "Ap.", designating it as an appoggiatura chord.

-Some chords can not be given a sensible Roman numeral analysis. It may come as a result of good voice leading but it might not always make sense in tonal music. The º7 chords often work in this category. Basically, this is when a traditional sonority used in a non traditional way. Some times we can make more sense of them by offering an alternate analysis.

-Below, we see all normal chords in the key of C major, except for measure 3.

-Here we have a D7 chord in C major. Normally, that D7 would act as a V7/V. HOWEVER, it does not go to V (G). Rather, it goes to iii (Em). If it was a V/iii, it would have been a B7 chord. But no! We can't really apply a proper function, in tonal harmony, in this scenario. What we have here is a SIMULTANEITY!