Degrees of the
Scale
VIII. tonic
VII. leading note
VI. submediant
V. dominant
IV. subdominant
III. mediant
II. supertonic
I. tonic
These are the generic degrees or steps in a diatonic scale. The words are the technical names for the degrees of the scale.
Looking at the piano keyboard, starting at C as the tonic, D is the supertonic, and so on. They can also be thought of as the Roman Numerals, I for C, II for D, and so on. Between C and D is a whole step, or whole tone, as there is between D and E, F and G, G and A, A and B. Between E and F is a half-step, a half-tone, or semitone, as there is between B and C.
From C in this manner, one plays a diatonic major scale.
Not only are the notes referred to by these words, and numerals, but also the chords built upon them. Generally, though, the chords are referred to by the numerals; the most important chords in most western harmony being I, or tonic, IV, or subdominant,
and V, or dominant.