Hyperborea comes from the Greek:
hyper: beyond.
ex: hyperspace, hyperactive
borea: north.
ex: aurora borealis
So Hyperborea is in the distant north, sometimes meaning Scandinavia.
In Greek myth, Hyperborea is a land to the north untouched by winter, often the winter home of Apollo. Some associate it with Atlantis.
As the southern Europeans warred with those in the north, the area took on aspects of of darkness as the home of giants, demons, and sorcerers.
Hyperborea became part of the Conan and Cthulhu mythos as Lovecraft, Howard, and Smith wrote in each others' universes. Conan visited Smith's Hyperborea, and Lovecraft's stories would refer to the vanished land's relics and writings.
More recent works with Hyperborea include Poul Anderson's Time Patrol, the film Sinbad and the Eye of the Tiger, and various role-playing games. It may be a source for the Blight in Robert Jordan's Wheel of Time.
Since most of my website deals with fantastic realms beyond the real world, I wanted a name to suggest an exotic land outside reality.