Normal space, only in the most simplistic of terms. The world, Yril, orbits the sun, and itself is orbited by a single moon; Lyri. The space between those three bodies is essentially the same as real-life space, though it might have considerably less radiation...if you knew how to check. The stars are 'really far away', and seem to be of different sizes, and move at wildly different rates; the biggest ones seem to move more quickly and regularly, however.
The *deities actually live on Yril, on inaccessable continents (except to elves and the dead, who both end up there eventually). If one was to sail across the sea, they might actually reach the Land of the Gods, but they would quickly be caught and killed/sent home by divine servants.
*Two of the four; one godess is the world, and the other lives on the moon. The two gods live on/slightly under the surface.