While Drukhari and Druchii have a different history, and Games Workshop mostly retconned the idea that the WHFB world existed somewhere in 40k, I have fairly little doubt you could find a WHFB Dark Elf calling themselves Eldar somewhere, at least in a "Eldar is the elven word" kind of way, and culturally they're pretty similar in theme. At least in the "BDSM reaver and slaver Elves that don't believe in consent" kind of way.

Tl;Dr Dark Eldar works for WHFB just fine, because they stole half their ideas and terms from Tolkien anyways. The rest they stole from Moorcock.

[–] [email protected] 1 points 10 months ago

Sure Dark Eldar works for Fantasy too, GW stole pretty much everything about Warhammer and cobbled it together. But still, the common nomenclature is DEldar for 40k (although I think they got some copryrightable name a few years ago) and DElfs for WHFB.