Which scale degree is referred to as the supertonic?

The supertonic is defined as the second degree of the diatonic scale. In any major or minor scale, the scale degrees are numbered starting from the tonic, which is the first degree. Therefore, when counting up from the tonic, the second note is the supertonic. This term comes from the Latin word "super" meaning "above" and "tonic," which clearly indicates its position relative to the first degree.

For instance, in the C major scale (C, D, E, F, G, A, B), the tonic (first degree) is C, making D the supertonic (second degree). Understanding the scale degrees, including the supertonic, is crucial for analyzing harmony and melodic construction in music theory.