Tonal harmony refers to the system of musical organization based on the hierarchy of pitches and chords within a key. It emphasizes the relationships between notes, particularly how they create tension and resolution. This system is foundational in Western music, guiding composers in creating melodies and harmonies that feel cohesive and satisfying. In tonal harmony, chords are built from scales, with the major and minor scales being the most common. Each chord has a specific function, such as the tonic (home chord), dominant (creates tension), and subdominant (prepares for resolution). Understanding these relationships helps musicians analyze and compose music effectively.