Loka is a Sanskrit word for "world".
In Jain texts, universe is referred to as Loka. Jain Cosmology postulates an eternal and ever-existing loka which works on universal natural laws, there being no creator & destroyer deity. According to the Jain cosmology, the universe is divided into 3 parts:
In the Puranas, and already in the Atharvaveda, there are fourteen worlds, seven higher ones (Vyahrtis) and seven lower ones (Pātālas), viz. bhu, bhuvas, svar, mahas, janas, tapas, and satya above and atala, vitala, sutala, rasaataala, talatala, mahaatala, patala and naraka below.
The scholar Deborah Soifer describes the development of the concept of lokas as follows:
The concept of a loka or lokas develops in the Vedic literature. Influenced by the special connotations that a word for space might have for a nomadic people, loka in the Veda did not simply mean place or world, but had a positive valuation: it was a place or position of religious or psychological interest with a special value of function of its own.
Hence, inherent in the 'loka' concept in the earliest literature was a double aspect; that is, coexistent with spatiality was a religious or soteriological meaning, which could exist independent of a spatial notion, an 'immaterial' significance.
In Early Buddhism, based upon the Pali Canon and related Agamas, there are four distinct worlds: There is the Kama Loka, or world of sensuality, in which humans, animals, and some devas reside, Rupa-Loka, or the world of refined material existence, in which certain beings mastering specific meditative attainments reside, and Arupa Loka, or the immaterial, formless world, in which beings to master formless meditative attainments reside. Arahants, who have attained the highest goal of Nibbana (or, Nirvana), have unbound themselves from individual (limited) existence in any form, in any realm, and cannot be found here, there, or in between, i.e., they are found in no Loka whatsoever.