Mixolydian mode explained
The fifth mode of the major scale, characterised by a major quality with a lowered seventh degree
In Depth
The Mixolydian mode sounds like a major scale with a flattened seventh, giving it a bluesy, laid-back quality. The interval pattern is W-W-H-W-W-H-W. The lowered seventh removes the leading tone's pull toward the tonic, creating a more relaxed resolution. Mixolydian is the foundation of blues-rock harmony, Celtic folk music, and much of the Beatles' output. The ♭VII chord in rock music — one of the most characteristic sounds of the genre — comes from Mixolydian.
Norwegian Wood by the Beatles is in the Mixolydian mode, which gives it its distinctive folk quality — the melody never resolves with the urgency of a leading tone.