Which of the following is NOT a mode listed in the acronym for musical modes?

The correct answer is "Harmonic" because the acronym for the musical modes encompasses the seven church modes derived from the diatonic scale. These modes include Ionian, Dorian, Phrygian, Lydian, Mixolydian, Aeolian, and Locrian. Each of these modes corresponds to different patterns of whole and half steps, leading to distinctive tonal characteristics.

Harmonic, while it may refer to a harmonic minor scale or other harmonic concepts, is not classified as one of the traditional modes. Instead, it typically pertains to a specific scale or approach in harmony rather than a mode derived from the seven-note scales. This distinction clarifies why Harmonic does not belong to the list of recognized modes in this context, while Ionian, Locrian, and Phrygian rightly belong to it.