|posted: 3/18/2008 at 1:09:05 PM ET|
I think you are talking about the chord symbols, not the notes, in which case the small circle would mean a diminished chord.
The diminished chord is built in thirds, just like every other chord, but the 3rd and the 5th degree of the chord are both lowered a half step.
In the case of a C diminished chord, rather than containing the notes C, E, and G (like a C major chord) the notes in the chord would be C, Eb, and Gb.
For a G chord it would be G, Bb, and Db, rather than G, B, and D. Hope this helps.