Harmony is a concept that is often used in music to describe the combination of different sounds together in order to create new, distinct musical ideas. Theories of harmony seek to describe or explain the effects created by distinct pitches or tones coinciding with one another; harmonic objects such as chords, textures, and tonalities are identified, defined, and categorized in the development of these theories. Harmony is broadly understood to involve both a "vertical" dimension (frequency-space) and a "horizontal" dimension (time-space), and often overlaps with related musical concepts such as melody, timbre, and form. In a narrower sense, harmony refers to the extensively developed system of chords and the rules that allow or forbid relations between chords that characterizes Western music.
Harmony can also be used to describe the agreement of ideas, feelings, or actions, or a pleasing combination of different parts outside of music. For example, one might imagine a society in which all races lived together in harmony.
In summary, harmony is a concept that can be used to describe the combination of different sounds together in music, as well as the agreement of ideas, feelings, or actions outside of music.
