Gbm11 chord

The G-flat minor eleventh chord (abbreviated Gbm11 chord) is a six-note chord consisting of the notes G♭, B♭♭, D♭, F♭, A♭, and C♭. The chord is formed by adding an eleventh to the G-flat minor ninth chord.

In practice, the fifth (D♭) is often omitted from the Gbm11 chord to avoid a very dissonant sound, and because it's not always possible to play all notes simultaneously.