The Unofficial High Elf Discussion Megathread

[Callistus-wyrmrest-accord]

The Highborne, or Quel’dorei, as Azshara had named them in ages past, would eventually set shore upon the eastern land men would call Lordaeron. They planned to build their own magical kingdom, Quel’Thalas, and reject the night elves’ precepts of moon worship and nocturnal activity. Forever after, they would embrace the sun and be known only as the high elves.

https://wow.gamepedia.com/Exile_of_the_High_Elves

According to this in game book, It’s just a name Azshara gave some Night Elves.