Texture is the relationship of melody to its accompaniment or to other melodies in a musical composition. The term is often used to refer to the relative thickness, or complexity, of the sound or to the type of compositional technique employed. Texture can be simple or elaborate, and is described with the following terms: monophonic (a single line of melody), biphonic (two different, simultaneous melodies), heterophonic, homophonic, or polyphonic. The word texture is used because adding different layers or elements to music creates a musical "tapestry."