Loka (Skt., ‘world’).

Hinduism

The domains or regions which make up the cosmos. In origin there were three lokas (triloka), locations inhabited by beings appropriate to them: earth, atmosphere, and ‘the yonder world’ (of the gods, the sun, the moon, and the stars). But these were early related to domains pertaining to salvation (and its opposite). Thus svar, ‘sky’, is already synonymous in the Vedas with svarga, ‘heaven’, so that another triad was produced of svarga-loka, bhūmi- (earth), and pātāla- (underworld or hell).

Buddhism

The primary sense is analytic, in which loka is the ‘habitat’ of gods and human beings. In these contexts, loka is explained as all the perceptible world, i.e. all that which comes within the spheres of the senses. Loka in its cosmographic sense includes the entire cosmos. A lokadhātu is a smaller unit within the loka, a unit which may be described as a solar system. Thus, the loka consists of myriads of such solar systems. Therefore, in its immensity, the loka is unlimited. It is not possible, therefore, to reach the end of the loka by travelling and its immensity cannot be grasped by thinking either. Hence, lokacintā is one of four unthinkables according to Anguttara Nikāya (2. 80).

Buddhism also has its equivalent to the triloka of Hinduism (in Pāli, trailokya or traidhātuka). They are (i) kāmaloka, the domains of desire and attachment, including those of hell (naraka), humans, animals, the devas, and the asuras; (ii) rūpaloka, the domain of form without desire, the gods in the dhyāna heaven, attained through the four dhyānas; (iii) arūpaloka, the domain of formlessness. They may also be known as Kāmadhatu, etc.