The lack of a minor or a major third in the chord creates an open sound, while the dissonance between the fourth and fifth or second and root creates tension. The term is borrowed from the here in your presence chords pdf technique of suspension, where a note from a previous chord is carried over to the next chord, and then resolved down to the third or tonic, suspending a note from the previous chord. In modern jazz, a third can be added to the chord voicing, as long as it is above the fourth. Each suspended chord has two inversions.
Suspended second chords are inversions of suspended fourth chords, and vice versa. Sevenths on suspended chords are “virtually always minor sevenths”, while the 9sus4 chord is similar to an eleventh chord and may be notated as such. Dominant seventh with added fourth, also written as a slash chord, followed by the tonic major seventh chord. A jazz sus chord or dominant 9sus4 chord is a seventh chord on the fifth scale degree of the key with a suspended fourth and an added ninth.
Functionally, it can be written as V9sus4 or V7sus9. G, which shows the merging of ii7 and V7.