A 'tonic scale', or 'equal tempered scale', is a musical scale consisting of 12 notes, 7 tonic and 5 semitonic. The notes are referred to by the names A, A sharp, B, C, C sharp, D, D sharp, E, F, F sharp, G, and G sharp.

The sharps are the semitones; each also has a second name, which is the letter following it appended by 'flat'; for example, A sharp is also B flat. Note also that there is no semitonic note for B sharp/C flat or E sharp/F flat; the interval betwen B and C, and E and F, is semitonal.

This is not to be confused with the 'chromatic' or 'diatonic' scale, which contains 17 distinct notes, each flat and each sharp being distinct (though very close).