Key

Key, musical term denoting the arrangement of notes in a certain kind of scale. On the piano keyboard there are 12 notes, black and white, between each octave, each of which can be the starting point for 2 scales, one in the major mode and one in the minor mode. Thus if a piece of music is written for a major scale starting on the note C, then the key of the piece will be C major. If the piece is written for the minor scale starting on the note G, then the key will be G minor. Major scales all have one particular sequence of pitch intervals between the notes, while all the minor scales have a different sequence of pitch intervals. To maintain the same sequence of pitch intervals for all the major and minor scales, adjustments to the pitch of individual notes need to be made from scale to scale. Notes will either need to be raised by half a tone (sharpened) or lowered by half a tone (flattened). The number of sharpened or flattened notes required for any key is called the key signature and is always written at the start of a piece. Each major key has a corresponding minor key in terms of a shared key signature. For example, a sharpened F is the key signature for both the key of G major and E minor; a flattened B indicates either the key of F major or D minor; and so on through the 24 major and minor keys.