The central tone around which melodies are built is rooted in a central tone. This tone goes by different names-the keynote, the root, or the tonic. "Key" involves not just the central tone, but also the central and related chords and scales. In this section, you will be introduced to tools that will help you identify and describe key signatures, as well other concepts relating to the tonal center of a piece, such as the "circle of fifths."