Drop 2 II

The Drop 2 II voicing of Abmaj7 stacks G, C, Eb and Ab from the bottom up: the major 7th, major 3rd, 5th and root of the chord.

It's one of the Drop 2 voicings: four-note chords in close position with the second note from the top dropped an octave, played over the root. The others for Abmaj7 are Drop 2 I, Drop 2 III and Drop 2 IV.