piano chord
G♯6
G♯1B♯3D♯5E♯6
A major triad with a sixth added. The same four notes as a minor seventh chord a third below.
Written the other way round it is A♭6 — the same twelve keys on a piano, a different piece of notation.
What is true of it
G♯6 is G♯, B♯, D♯ and E♯ — 1, 3, 5 and 6 counted from G♯.
These are also the notes of Fm7/G♯. Which name is right depends on what is underneath and what came before — the notes alone do not decide.
On an instrument that cannot reach all 4, the 5 goes first, in that order.