Injazzmusic, thelydian chord is themajor 7♯11 chord,[1] or♯11 chord, thechord built on the firstdegree of theLydian mode, the sharpeleventh being acompoundaugmented fourth. This chord, built on C, is shown below.
This is described as "beautiful" and "modern sounding."[1] 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 themajor scale.
Major 7♯11 may also refer to theLydian augmented chord, anaugmented seventh chord with augmented fourth appearing in theLydian augmented scale.[2]
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.[1]
Lydian chords may function assubdominants orsubstitutes for thetonic in major keys.[3] Thecompound interval of theaugmented eleventh (enharmonically equivalent to♯4, the characteristic interval of theLydian mode) is used since the simple fourth usually only appears insuspended chords (which replace the third with a natural fourth, for example Csus4). The fifth can be omitted to avoid creating dissonance with the♯4; this is usually not specified in chord naming.
The dominant 7♯11 orLydian dominant (C7♯11) comprises the notes:
(Note that in jazzlead sheet notation, upper extensions (intervals beyond the 7th) aren't named unless they are altered; alternatively, when including the 9th and 13th this chord could be called a C13♯11.)
Basing this chord on the pitch C results in the pitches:
The same chord may also be voiced:
Thisvoicing omits the perfect fifth (G) and raises the major ninth (D) by an octave. The augmented eleventh (F♯) is also played twice in two different registers. This is known as "doubling".
