Guitar Glossary: Degree
The numbers given to the notes in a scale based on the interval from the root, usually in Roman numerals. In C: C = I, D = II, E = III, F = IV, G =V, A = VI and B = VII. These numbers are used when discussing the relatioship between notes regardless of key. For example, a change from the I chord to the IV has the same overall effect in A as it does in Eb.