Scale degrees

Naming a note "F♯" tells you which pitch it is. Naming it "the leading tone of G major" tells you what it does. Scale degrees are the second kind of name, and they are what makes theory transferable between keys.

The seven names

1. C1
   tone
2. D2
   tone
3. E3
   semi
4. F4
   tone
5. G5
   tone
6. A6
   tone
7. B7
   semi
8. C8

The three that matter most

Tonic (1). The note the music treats as home. A piece ends on it and returns to it.

Dominant (5). A perfect fifth above the tonic, and the note with the strongest gravitational pull back. The chord built on it is what produces the sense of an ending.

Leading tone (7). A semitone below the tonic, and that semitone is the entire point — it sounds unfinished until it resolves upwards.

That third one explains an oddity in minor keys. The natural minor's seventh degree is a whole tone below the tonic, not a semitone, so it does not lean. When it is a whole tone below it is properly called the subtonic. Raising it to create a genuine leading tone is exactly why the harmonic minor exists.

The "sub" prefix is not what it looks like

Subdominant does not mean "below the dominant" in the scale order. It means a fifth below the tonic — mirroring the dominant, which is a fifth above.

• Dominant: a fifth up from C is G.
• Subdominant: a fifth down from C is F.

Same for submediant: a third down from the tonic, mirroring the mediant a third up. In C, the mediant is E and the submediant is A.

How they are written

Several notations coexist:

• Arabic numerals — 1, 2, 3. Common in pop and jazz teaching.
• Carets — 1̂, 2̂, 3̂. The academic convention for melodic degrees.
• Roman numerals — I, ii, iii. These refer to the chords built on each degree, not the notes. See Roman numerals.

Why bother

Because it makes patterns portable. "The melody goes 5–1–2–3" describes a shape that works in every key. "The melody goes G–C–D–E" describes it only in C.

Once you hear music in degrees, transposing stops being arithmetic and the same progression stops looking like a different progression in each key.