(Sanskrit लोक, "world, region, race, community, humanity, place, space, district" from loc, "to shine, be bright, visible.") In Hinduism and Buddhism, lokas are the wide range of manifested regions or worlds, which is why they are "what can be seen" (lokyante). They are generally discussed as three (triloka) or seven but are truthfully innumerable, since loka is a general term for any world or region. Most importantly, each is related to a state of consciousness.
"There are seven planes. They are Bhuloka (earth plane), Bhuvarloka (Antariksha or the astral plane), Svargaloka (heaven or the mental plane), Maharloka, Janaloka, Tapoloka and Satyaloka (Brahmaloka or the world of Brahma, the Creator). Tapasvins dwell in Tapoloka. If you keep different kinds of lights in a room such as kerosene oil light, mustard oil light, petromax, candle light, electric light; the various lights interpenetrate in the room. Even so, the Lokas interpenetrate. Each plane has its own matter of an appropriate degree of destiny, which interpenetrates the matter of the plane next below it. The astral plane, or Bhuvarloka, interpenetrates the earth plane and extends for some distance beyond it. The mental plane interpenetrates the astral but also extends further into space than does the latter. The vibrations of the astral world are more rapid or quicker than those of the physical plane. The vibrations of the mental plane are more rapid or quicker than those of the astral plane. The vibrations of the Satyaloka are more rapid or quicker than those of the mental plane. In each plane the soul develops a new and higher sense of power. When you pass from one plane to another you do not move in space. You simply change your consciousness. You change your focus of consciousness. You can have different sorts of vision through the telescope or microscope by using lenses of different degrees of potency or power. You have got different vehicles within yourself which correspond to different planes and which can function in different planes." —Swami Sivananda