piano chord
D♯maj9
D♯1F𝄪3A♯5C𝄪7E♯9
A major seventh with a ninth on top.
Written the other way round it is E♭maj9 — the same twelve keys on a piano, a different piece of notation.
What is true of it
D♯maj9 is D♯, F𝄪, A♯, C𝄪 and E♯ — 1, 3, 5, 7 and 9 counted from D♯.
F𝄪 and C𝄪 are double sharps, and they have to be: every letter from D♯ upwards is used once, so the 3 cannot be written any other way.
On an instrument that cannot reach all 5, the 5 and 1 go first, in that order.