Functional harmony refers to the way chords and progressions are organized in music to create a sense of movement and resolution. It is based on the relationships between different chords, particularly how they relate to the tonic, or home chord. This system helps composers and musicians understand how to build tension and release in their music. In functional harmony, chords are often categorized into three main functions: tonic, dominant, and subdominant. The tonic serves as the home base, the dominant creates tension that seeks resolution, and the subdominant acts as a bridge between the two. This framework is foundational in many styles of Western music, including classical and jazz.