diminished scale
theorydih-MIN-isht scale
A symmetrical scale alternating whole and half steps, dividing the octave into repeating patterns
The diminished scale (also called the octatonic scale) contains eight notes and comes in two forms: whole-half (W-H-W-H-W-H-W-H) and half-whole (H-W-H-W-H-W-H-W). Its symmetry means there are only three distinct diminished scales. The scale contains all the notes of two diminished seventh chords a half step apart. Rimsky-Korsakov used it extensively, and it became fundamental to jazz improvisation over diminished and dominant chords. Messiaen classified it as his second mode of limited transposition.
Rimsky-Korsakov used the diminished scale so extensively that in Russia it is simply called the Rimsky-Korsakov scale.