piano chord
G♯maj7
G♯1B♯3D♯5F𝄪7
Major triad with a major seventh: a half step below the root, an octave up.
Written the other way round it is A♭maj7 — the same twelve keys on a piano, a different piece of notation.
What is true of it
G♯maj7 is G♯, B♯, D♯ and F𝄪 — 1, 3, 5 and 7 counted from G♯.
F𝄪 is a double sharp, and it has to be: every letter from G♯ upwards is used once, so the 7 cannot be written any other way.
On an instrument that cannot reach all 4, the 5 goes first, in that order.