MusicaLexica

Starting with a G Major chord (G - B - D), we can modify each note one by one and produce different chords.  This is a good exercise to help figure out what kind of chord you’re looking at when you know a base chord.

G - B - D: G Major

G - Bb - D: G minor

Both major and minor chords have an interval of a fifth.  In the case of G, the fifth is G - D (G = 1, A = 2, B = 3, C = 4, D = 5).  The difference between a major chord and a minor chord relies totally on the third, which for G is B for a G Major, and Bb for a G minor.

G - Bb - D: G minor

G - Bb - Db: G diminished

The diminished chord has a lowered third and a lowered fifth.  From a G minor, we lower the fifth (D -> Db) and produce a diminished chord.

G - B - D: G Major

G - B# - D#: G augmented

An augmented chord has a raised third and a raised fifth.  It’s true that B# is enharmonic to C (that is, they have the same sound), but to show that we’re treating it as an augmented third, we indicate it as B#.

G - B - D: G Major

G - A - D: G sus2

G - C - D: G sus4

The A is the second note in the G scale.  Replacing the third with the second makes a suspended 2 chord.

C is the fourth note in the G scale.  Replacing the third with the fourth makes a suspended 4 (or sus4 or sus) chord.  The same note as C was called B# in the G augmented chord to emphasize the fact that it’s working as an augmented third in that chord.  In a sus4 chord it’s behaving as a fourth.  It’s mostly convention but it gets the point across that a G suspended chord does not have a third…that’s what gives it that airy sound.  It’s not a major or minor chord.