Music is an art form and cultural activity whose medium is sound organized in time. The common elements of music are pitch (which governs melody and harmony), rhythm (and its associated concepts tempo, meter, and articulation), dynamics (loudness and softness), and the sonic qualities of timbre and texture (which are sometimes termed the "color" of a musical sound). Different styles or types of music may emphasize, de-emphasize or omit some of these elements. Music is performed with a vast range of instruments and vocal techniques ranging from singing to rapping; there are solely instrumental pieces, solely vocal pieces (such as songs without instrumental accompaniment) and pieces that combine singing and instruments. The word derives from Greek μουσική (mousike; "art of the Muses"). See glossary of musical terminology.
Performing arts are a form of art in which artists use their voices or bodies, often in relation to other objects, to convey artistic expression. It is different from visual arts, which is when artists use paint, canvas or various materials to create physical or static art objects. Performing arts include several disciplines, each performed in front of a live audience.
A chord is by no means an agglomeration of intervals. It is a new unit which, although dependent on the formative power of the single interval, is felt as being self-existent and as giving to the constituent intervals meanings and functions which they otherwise would not have.
Paul Hindemith (1952: 72). A Composer's World. Cambridge, Mass.