piano chord
D♯11
D♯1F𝄪3A♯5C♯♭7E♯9G♯11
Six notes in theory; in practice the third is usually dropped, because the eleventh sits a half step above it.
Written the other way round it is E♭11 — the same twelve keys on a piano, a different piece of notation.
What is true of it
D♯11 is D♯, F𝄪, A♯, C♯, E♯ and G♯ — 1, 3, 5, b7, 9 and 11 counted from D♯.
F𝄪 is a double sharp, and it has 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 6, the 3, 5 and 1 go first, in that order.