refers to the relative position in the scale,, with the first note of the scale being scale degree 1, and is also called the tonic. The second is scale degree 2, the third is scale degree 3, etc. - until we arrive at the tonic again.
A relative system for naming pitches according to their position in some scale. For Western music, seven scale degrees are commonly identified. For the major scale, the most well-known names are the "solfa" syllables: do, re, mi, fa, so, la, ti. For both the major and minor scales, theorists use the names: tonic, supertonic, mediant, subdominant, dominant, submediant, leading tone, or more simple, the numbers 1^, 2^, 3^, 4^, 5^, 6^, 7^.