SB 5.20.36

lokāloka iti samākhyā yad anenācalena lokālokasyāntarvar-tināvasthāpyate.

loka—with light (or with inhabitants); alokaḥ—without light (or without inhabitants); iti—in this way; samākhyā—designation; yat—which; anena—by this; acalena—mountain; loka—of the land inhabited by living entities; alokasya—and of the land not inhabited by living entities; antarvartinā—which is in the middle; avasthāpyate—is established.

Between the lands inhabited by living entities and those that are uninhabited stands the great mountain which separates the two and which is therefore celebrated as Lokāloka.