The half diminished scale is a seven-note musical scale. It is more commonly known as the Locrian 2 scale or the Aeolian 5 scale, names that avoid confusion with the diminished scale and the half-diminished seventh chord (minor seventh, diminished fifth). It is the sixth mode of the ascending melodic minor scale.
In the key of B, the half-diminished scale built on C is associated with Cm<sup>75</sup>, which functions as a ii<sup>7</sup> chord in minor (see chord-scale system).