Csus4

Csus4, short for C suspended fourth, is a chord used to create a suspended, tense color in music. It is built from the C major triad (C–E–G) with the third (E) replaced by the fourth (F). The basic sonority is C–F–G, and players often add an octave C or other voices to flesh out the sound.

Functionally, the absence of the third means Csus4 does not specify major or minor tonality, producing temporary tension that typically resolves to C major (C–E–G) when the F moves down to E. It can also resolve to Csus2 (C–D–G) or other chords, depending on voice leading and arrangement. In practice, Csus4 is a common color chord in many genres, including pop, rock, folk, jazz, and classical contexts.

Notationally, the chord is written as Csus4. Variants include Csus4(add9), which adds D (C–F–G–D), and Csus4(7) or C7sus4, which includes a seventh (Bb) while retaining the suspended fourth (C–F–G–Bb). On keyboards and guitars, Csus4 can be voiced in multiple positions, from simple three-note voicings to richer textures that sustain the F while other notes move.

Overview: Csus4 serves as a color or tension chord rather than a standalone harmonic goal. It is commonly used to create interest before resolving to C major, and it appears across many musical styles as a tool for smooth voice-leading and expressive color. See also Csus2 and suspension chords.