SB 5.20.36

lokāloka iti samākhyā yad anenācalena lokālokasyāntarvar-tināvasthāpyate.
Synonyms: 
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.
Translation: 
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.