Music Theory Reference


A key is a family of notes of a specific scale and of the chords built up of the notes. In the case of the C major scale we have seven notes C, D, E, F, G, A and B. And the seven matching chords: C, Dm, Em, F, G, Am, and Bdim.

Depending on the type of the scale the key is built up on, it can be either major or minor. E.g. if the C major scale is used as the foundation of the key, then the key is also major.

Popular songs are usually in a key meaning that the melody is built up only from the notes of the key and only the chords of the key are used for the accompaniment. Here is an example of a world famous song in the C major key.