Ifing (Scand.). The broad river that divides Asgard, the home of the gods, from that of the Jotuns, the great and strong magicians. Below Asgard was Midgard, where in the sunny æther was built the home of the Light Elves. In their disposition and order of locality, all these Homes answer to the Deva and other Lokas of the Hindus, inhabited by the various classes of gods and Asuras.
Source: H.P.Blavatsky - The Theosophical Glossary