piano chord
G♯9
G♯1B♯3D♯5F♯♭7A♯9
A dominant seventh carrying a ninth on top.
Written the other way round it is A♭9 — the same twelve keys on a piano, a different piece of notation.
What is true of it
G♯9 is G♯, B♯, D♯, F♯ and A♯ — 1, 3, 5, b7 and 9 counted from G♯.
On an instrument that cannot reach all 5, the 5 and 1 go first, in that order.