The minor key and major key in music refer to the mode. The specific content refers to the relationship between the tonic tone of the mode and the other six tones. For example

The relationship between the seven notes of the major scale is: major second - major second - minor second - major second - major second - major second - minor second. The simple notation is 1-2-3-4-5-6-7-1 (add the high and low points yourself)

The relationship between the seven tones of the minor scale are: major second - minor Second degree - major second degree - major second degree - minor second degree - major second degree - major second degree. The simple notation is 6-7-1-2-3-4-5-6 (add the high and low points yourself)

A, B, C, D. The key refers to the specific number 1 in the simple notation pitch. For example

A major and #f minor both belong to the key of A;

B major and #g minor both belong to the key of B;

Both C major and a minor It belongs to the key of C;

D major and b minor both belong to the key of A, etc.