Lydian chord

In jazz music, the lydian chord is the major 7♯11 chord, or ♯11 chord, the chord built on the first degree of the Lydian mode, the sharp eleventh being a compound augmented fourth. This chord, built on C, is shown below.

This is described as "beautiful" and "modern sounding." The notes that make up the Lydian chord represent five of the seven notes of the Lydian mode, and the ♯11 at the top of the chord is the ♯4 (one octave higher) that distinguishes the Lydian mode from the major scale.

Major 7♯11 may also refer to the Lydian augmented chord, an augmented seventh chord with augmented fourth appearing in the Lydian augmented scale.

In a chord chart, the notation "Lydian" indicates a major family chord with an added augmented eleventh, including maj7♯11, add9♯11, and 6♯11.