When we refer to the nth degree of a certain scale we mean to say that the scale is played starting from the note at the nth position. The point of starting is thus the note of the scale in the nth position with respect to the tonic note.
Degree may be written out in plain words (first, second, third, fourth, fifth, sixth, and seventh degrees of the scale), by Roman numerals (Capital for major scales – I, II, III, IV, V, VI and VII, and small letters for minor scales – i, ii, iii, iv, v, vi and vii) or by using the English names viz. tonic, supertonic, mediant, subdominant, dominant, submediant and leading note. These names are derived from a scheme where the tonic note is the 'center'. Supertonic is one step above the tonic; mediant and submediant are each a third above and below the tonic, and dominant and subdominant are a fifth above and below the tonic. The term, subtonic refers to the VII the mode that has been flattened by a semitone; leading note when that interval is a half step.
Read example...Scale Degree - tonic, supertonic, mediant, subdominant, dominant, submediant and leading note
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