Harmonic structure refers to the way chords and harmonies are organized in a piece of music. It involves the relationships between different chords and how they progress throughout a composition, creating a sense of movement and emotion. Understanding harmonic structure is essential for musicians and composers, as it forms the backbone of musical expression. In Western music, harmonic structure often follows specific patterns, such as the use of triads and seventh chords. These elements work together to create tension and resolution, guiding the listener's experience. By analyzing harmonic structure, one can gain deeper insights into the overall form and style of a musical work.