In the prophecies of Isaiah (ch. 62, v. 4), a name to be given to Israel when she is at one with God. Beulah in Hebrew means ‘married’.
In Bunyan's Pilgrim's Progress, the Land of Beulah is a pleasant and fertile country beyond the Valley of the Shadow of Death, and within sight of the Heavenly City; the name may thus be used for heaven itself.
In William Blake's writing, Beulah stands for a state of light, which is symbolized by the moon.