G Suspended 4th
sus4
0 - 5 - 7Root + perfect 4th + perfect 5th
About G Suspended 4th
Gsus4 replaces the B in a G major chord with a C, and on guitar that means adding a finger to a shape that already uses three. The result leans firmly toward plain G, which is why the chord appears mainly as a hesitation before the tonic rather than as a harmony in its own right.
The notes
G, C, D. No third, so no mode; the C sits a semitone above the B it replaced and wants to fall back down.
Because the fourth is the note that defines the chord, voicings that omit it are not sus4 at all — a common error when players simplify the shape and end up with a plain G with a doubled root.
On the fretboard
The usual fingering keeps the G shape and adds the C on the B string at the first fret, or frets the third fret of the B string and the first of the high E depending on which voicing is wanted.
The figure is heavier than its D or A equivalents because G uses more fingers to begin with — one reason players often capo to play these suspensions in an easier shape.
Where it shows up
In the key of G before the tonic, and in the key of D as a suspended IV. Worship and folk music use it constantly, usually resolving within the same bar.
It also serves as a way to keep a static G moving over several bars: alternating G and Gsus4 provides motion without any harmonic change at all.
The chord is also the easiest way to end a song on G without finality: hold the suspension, let it ring, and stop before the resolution. The listener supplies the missing chord themselves.