A suspended chord (or sus chord) is a musical chord in which the (major or minor) third is omitted and replaced with a perfect fourth or a major second. 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. When using popular-music symbols, they are indicated by the symbols "sus4" and "sus2". For example, the suspended fourth and second chords built on C (C–E–G), written as Csus4 and Csus2, have pitches C–F–G and C–D–G, respectively.
{
\override Score.TimeSignature #'stencil = ##f
\relative c' {
\clef treble
\time 4/4
\key c \major
1 1
} }
Suspended fourth and second chords can be represented by the integer notation {0, 5, 7} and {0, 2, 7}, respectively.
The term is borrowed from the contrapuntal 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. However, in modern usage the term concerns only the notes played at a given time – the suspended tone does not necessarily resolve and is not necessarily "prepared" (i.e., held over) from the prior chord. As such, after Csus4 (C–F–G), F may resolve to E (or E, in the case of C minor), but in rock and popular music the term indicates only the harmonic structure with no implications about what comes before or after, though preparation of the fourth still occurs about half the time and traditional resolution of the fourth occurs usually. 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. For example, Gsus2 (G–A–D) is the first inversion of Dsus4 (D–G–A) which is the second inversion of Gsus2 (G–A–D). The sus2 and sus4 chords both have inversions that create quartal and quintal chords (A–D–G, G–D–A) with two stacked perfect fourths or perfect fifths.