In medieval and modern music, the Lydian mode is a diatonic (seven-note) scale or musical mode which corresponds to the white keys of the piano from F to F. It may be considered an “excerpt” of a major scale played from the pitch a perfect fourth above the major scale's tonic, i.e., a major scale played from its fourth scale degree up to its fourth degree again. If we build a chord on the tonic, third and fifth, it is still a major chord.
The Lydian mode is actually equivalent to the major scale but with the fourth degree raised by a semitone.
Care must be exercised in identifying songs or pieces based in Lydian mode. It is common for listeners to confuse Lydian mode, particularly at the beginning of a piece, with an extended section based on the subdominant chord in a major key. So, for example, a piece in C major with a heavy emphasis on the chord of F major before the C tonality has been convincingly established, could be heard as centering around F, with a raised fourth.
Some notable compositions in Lydian mode:
- “Messe in der lydische Tonart” (Mass in the Lydian Mode) by Simon Sechter
- String Quartet No. 15 in A minor, Op. 132 by Ludwig van Beethoven, titled by the composer “Heiliger Dankgesang eines Genesenen an die Gottheit, in der lydischen Tonart” (“Holy Song of Thanksgiving by a Convalescent to the Divinity, in the Lydian Mode”)
- “Os justi” by Anton Bruckner
Two-octave Lydian scales are also available: PDF