All chords are basically structured exactly the same way

Definition
Chords are fundamentally Tetrads (4-note chords) constructed in the series of fifths, shown on the left, the back-bone of the World of PITCH. For the direction of chord progressions, we will use the expressions "flattening" (for "descending") and "sharpening" (for "ascending") because the flat notes are below and the sharp notes above.

NOTE
Triads (3-note chords) are incomplete Tetrads.

Let's look at an example - seeTHE USE OF COLOR

Construction of a chord
Two notes of every chord
          (in this case, the root, "G", and the fifth, "D")
     are already in the series of fifths:
          they are theFRAME(primary notes) of the chord.
The third of the chord, major or minor, "B",
     is placed inside theFRAME, almost in the center.
The seventh (or sixth)
     is placed outside theFRAME, as close as possible to it:
          the chord will possess a seventh, "F",
               if it progresses "downward" a fifth in a flattening direction;
          the chord will possess a sixth
               if it progresses "upward" a fifth in a sharpening direction,
               seeCHROMINICISM.
     The third and seventh (or sixth)
          are the secondary notes of the chord.

In musical compositions,
chords will not necessarily appear in the inversion presented.
It was chosen, however, as the most useful for explaining their structure.

Terminology
In order to use general terms
          that will apply to as many circumstances as possible,
     the following terminology will be used.
The primary notes of theFRAMEwill be called:
     theCOMMON TONE(which is common to both chords of the progression)
          and
     thePROPER TONE(which is specific to each chord of the progression).
The secondary notes are:
     theMEDIAN(the third, major or minor),
          which determines the mode of the chord; and
     theMOTRIX(the seventh or sixth) which imparts movement to the chord
          and determines the direction which it will take.

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