What are active chords in music theory?

Active chords, also known as dominant or tension chords, are those that create a sense of instability or expectation within a musical context. They are characterized by their need to resolve to a more stable chord, often referred to as a rest chord, which provides a feeling of completion or resolution. This tension and resolution is a fundamental aspect of Western music, allowing composers and performers to create emotional depth and movement within a piece.

Chords that require no resolution would be considered stable rather than active, making them less relevant to the concept of active chords. Major chords can be active or stable depending on their context, and are not inherently categorized as active. Lastly, the manner in which a chord is played, such as legato style, does not define whether it is an active chord, as this pertains more to articulation than to functional harmony. Therefore, the choice that active chords seek resolution in a rest chord is the most accurate definition.