In music theory, scale degree refers to the position of a particular note on a scale relative to the tonic, the first and main note of the scale from which each octave is assumed to begin. Degrees are useful for indicating the size of intervals and chords, and whether they are major or minor.
In the most general sense, the scale degree merely is the number given to each step of the scale, usually starting with 1=tonic. Defining it like this implies that a tonic is specified. For instance the 7-tone diatonic scale may become the major scale once the proper degree has been chosen as tonic (e.g. the C-major scale C-D-E-F-G-A-B, in which C is the tonic). If the scale has no tonic, the starting degree must be chosen arbitrarily. In set theory, for instance, the 12 degrees of the chromatic scale usually are numbered starting from C=0, the twelve pitch classes being numbered from 0 to 11.
In a more specific sense, scale degrees are given names that indicate their particular function within the scale. This definition implies a functional scale, as is the case in tonal music.
The expression scale step is sometimes used synonymously with scale degree, but it may alternatively refer to the distance between two successive and adjacent scale degrees (see Steps and skips). The terms "whole step" and "half step" are commonly used as interval names (though "whole scale step" or "half scale step" are not used). The number of scale degrees and the distance between them together define the scale they are in.
|Degree||Name (Diatonic Function)||Corresponding mode (major key)||Corresponding mode (minor key)||Meaning||Note (in C major)||Note (in C minor)|
|1st||Tonic||Ionian||Aeolian||Tonal center, note of final resolution||C||C|
|2nd||Supertonic||Dorian||Locrian||One whole step above the tonic||D||D|
|3rd||Mediant||Phrygian||Ionian||Midway between tonic and dominant, (in minor key) root of relative major key||E||E♭|
|4th||Subdominant||Lydian||Dorian||Lower dominant, same interval below tonic as dominant is above tonic||F||F|
|5th||Dominant||Mixolydian||Phrygian||2nd in importance to the tonic||G||G|
|6th||Submediant||Aeolian||Lydian||Lower mediant, midway between tonic and subdominant, (in major key) root of relative minor key||A||A♭|
|7th||Leading tone(in Major scale) / Subtonic (in Natural Minor Scale)||Locrian||Mixolydian||Melodically strong affinity for and leads to tonic/One half step below tonic in Major scale and whole step in Natural minor.||B||B♭|
|1st (8th)||Tonic (octave)||Ionian||Aeolian||Tonal center, note of final resolution||C'||C'|