A major scale is a scale that uses this whole/half step pattern: W-W-H-W-W-W-H. Adding another whole step to this pattern will bring you to the octave of the root (starting) note. If you start on any note and apply this step pattern, you’ll find the notes in the major key named after your starting note (the root of the scale).
A major scale guitar key can be defined as the key you’re playing any given song in on your guitar. As I said earlier, this is determined by the starting (root) note of the scale and the intervals of the notes you play.
The C major scale is: C-D-E-F-G-A-B-C (octave). Note there is a whole step between each of these notes (no sharps or flats) except for E/F and B/C, which are separated by half steps. This is because E/F and B/C are always a half step apart (no sharps or flats between them). This is always the case.
The major scale (along with the minor scale) is the building block of many musical forms, including country, pop, and rock. By adding or subtracting notes from the major scale, we can create other scales and modes used to add color and variety to music. All of it, however, begins with a good understanding of major scale structure.
Here are the degrees of the major scale and the chord type built on each degree.
In the key of C, the triads built on each of these scale degrees are Cmaj-Dmin-Emin, Fmaj-Gmaj-Am-B diminished. This same chord structure applies to all major scales and ensures that major scale guitar chords built on each of these root notes use only the notes of the major scale.
The sixth note of any major scale is its relative minor. In the key of C the sixth note is A, so starting on A and playing through the notes will give you the A minor scale. The notes are the same notes as the notes in C major, but since you start on A the pattern of steps is different, making it a minor scale rather than a major scale.