Demystifying Chord Symbols

Here I, hopefully not too feebly, explain how the chords got their names.

To create dominant chords I used a two octave C Mixolydian scale...

CDEFGABbCDEFGABbC

C - CEG
C7 - CEGBb
C9 - CEGBbD
C11 - CEGBbDF
C13 - CEGBbDFA

To create Major versions I used a two octave C Major scale...

CDEFGABCDEFGABC

C - CEG
Cmaj7 - CEGB
Cmaj9 - CEGBD
Cmaj11 - CEGBDF
Cmaj13 - CEGBDFA

To create Minor versions I used a two octave C Dorian scale...

CDEbFGABbCDEbFGABbC

Cm - CEbG
Cm7 - CEbGBb
Cm9 - CEbGBbD
Cm11 - CEbGBbDF
Cm13 - CEbGBbDFA

If you want to go insane get Chord Chemistry by Ted Greene.