"Mirabillis" translates roughly to "place of wonders" or "amazing/wonderful world" in the ancient language of the Honai, or early humans. While rarely used in day-to-day conversation it is the name for the whole world in which the known realms are sat; Mirabillis is the wide world of wonders wherein the lands under the sun and the abodes beneath the ground all have their being.
For those who understand such things, Mirabillis is the name of the great orb, or planet on which the vast oceans and varied lands of the realms - known and unknown - were placed by the gods of creation long before the ages of the Habens, Duarden, or Ghorsht.
According to the Wise Towers in Baaltar, Mirabillis is one of ten planetary bodies in the heavens. Each heavenly orb corresponds to an aspect of divine and natural order and is linked to various gods/goddesses across cultures. The ten heavenly bodies, all visible with the naked eye at varying times of the year and under certain circumstances are listed below along with their religious or astrological correspondences*.
* Astrological information above is taken from the commonlore of the northern realms and midrealms which is largely informed by the combined and syncretized beliefs of the Guth-Umbrige amalgamation and later influences of the Baaltaran Empire and post-Imperial feudal order.