What does the term sp mean in music?

In music, the term "sp" stands for "sub-dominant parallel." It refers to a chord progression that moves from the subdominant chord (the fourth chord in a major or minor scale) to the dominant chord (the fifth chord in a major or minor scale), but with the same root note.

For example, in the key of C major, the subdominant chord is F major and the dominant chord is G major. An sp progression would be from F major to G major, both with the same root note of C.

Sp progressions are often used in jazz, blues, and rock music to create a sense of tension and resolution. They can also be used to add variety to a chord progression.