Trilokam
त्रिलोकम्
The Three Worlds
The spirit of man has two dwellings: this world and the world beyond. There is also a third dwelling place: the land of sleep and dreams. Resting in this borderland, the spirit of man can behold his dwelling in this world and in the other world afar; and wandering in this borderland, he beholds behind him the sorrows of this world, and in front of him he sees the joys of the beyond. §
Śukla Yajur Veda, Bṛihadāraṇyaka Upanishad 4.3.9. UPM, 134§