What role does sus play in music theory and how is it used in creating harmonies and chord progressions?

The sus chord, short for suspended chord, is used in Music Theory to create tension and release in harmonies and chord progressions. It replaces the third of a chord with either the second or fourth note of the scale, creating a sense of suspension that resolves back to the original chord. This adds depth and interest to the music, enhancing the overall sound and emotional impact.