Trailokya has been translated as "three worlds," "three spheres," "three planes of existence," "three realms" and "three regions."
These three worlds are identified in Hindu and early Buddhist texts, have counterparts in Brahmanical sources and are elaborated upon by more recent Theosophical theory.

Buddhist cosmology

In Buddhism

Buddhism

Buddhism is a religion and philosophy encompassing a variety of traditions, beliefs and practices, largely based on teachings attributed to Siddhartha Gautama, commonly known as the Buddha . The Buddha lived and taught in the northeastern Indian subcontinent some time between the 6th and 4th...

, the three worlds refer the following karmic

Karma

Karma in Indian religions is the concept of "action" or "deed", understood as that which causes the entire cycle of cause and effect originating in ancient India and treated in Hindu, Jain, Buddhist and Sikh philosophies....

 rebirth destinations:

• Kāmaloka:
  world of desire, typified by sexual and other desires, populated by hell beings, animals, ghosts, humans and lower demi-gods.
• Rūpaloka:
  world of form, predominately free of baser desires, populated by jhana-dwelling gods, possible rebirth destination for those well practiced in jhanic absorption.
• Arūpaloka:
  world of formlessness, noncorporal realm populated with four heavens, possible rebirth destination for practitioners of the four formlessness stages.

Brahmanical system

Bhuvanatraya is the brahmanical fourfold division of worlds. These systems can be juxtaposed in the following manner:

Brahmanical Worlds		Buddhist Worlds
1. Bhur, earth.		1. World of desire, Kamadhatu or Kamaloka.
2. Bhuvah, heaven, firmament.		2. World of form, Rupadhatu.
3. Swar, atmosphere, the sky.	}	3. The formless world, Arupadhatu.
4. Mahar, eternal luminous essence.

Each of the brahmanical worlds represents a post-mortem state.

Theosophical views

According to Blavatsky's posthumously published Theosophical Glossary (1892):

• Kamaloka (or kamadhatu) is the world of Mara
  Mara (demon)
  In Buddhism, Māra is the demon that tempted Gautama Buddha by trying to seduce him with the vision of beautiful women who, in various legends, are often said to be Mara's daughters. In Buddhist cosmology, Mara personifies unwholesome impulses, unskillfulness, the "death" of the spiritual life...
  
  . Kamaloka has, like every other world, its seven divisions, the lowest of which begins on earth or invisibly in its atmosphere; the six others ascend gradually, the highest being the abode of those who have died owing to accident
  Accident
  An accident or mishap is an unforeseen and unplanned event or circumstance, often with lack of intention or necessity. It implies a generally negative outcome which may have been avoided or prevented had circumstances leading up to the accident been recognized, and acted upon, prior to its...
  
  , or suicide
  Suicide
  Suicide is the act of intentionally causing one's own death. Suicide is often committed out of despair or attributed to some underlying mental disorder, such as depression, bipolar disorder, schizophrenia, alcoholism, or drug abuse...
  
   in a fit of temporary insanity
  Insanity
  Insanity, craziness or madness is a spectrum of behaviors characterized by certain abnormal mental or behavioral patterns. Insanity may manifest as violations of societal norms, including becoming a danger to themselves and others, though not all such acts are considered insanity...
  
  , or were otherwise victims of external forces. It is a place where all those who have died before the end of the term allotted to them, and whose higher principles do not, therefore, go at once into Devachan
  Devachan
  Devachan is the "dwelling of the gods" according to the original teachings of Theosophy as formulated by H.P. Blavatsky.-Theosophy:Devachan is regarded as the place where most souls go after death where desires are gratified, corresponding to the Christian belief in Heaven...
  
  ic state—sleep a dreamless sweet sleep of oblivion, at the termination of which they are either reborn immediately, or pass gradually into the Devachanic state. This is that which medieval and modern Kabalists call the world of astral light, and the "world of shells".

• Rupaloka (or rupadhatu) is the celestial world of "form" (rupa), or what we call "Devachan." With the uninitiated Brahmans, Chinese and other Buddhists, the Rupadhatu is divided into eighteen Brahma or Devalokas; the life of a soul therein lasts from half a Yuga
  Yuga
  Yuga in Hindu philosophy is the name of an 'epoch' or 'era' within a cycle of four ages. These are the Satya Yuga, the Treta Yuga, the Dvapara Yuga, and finally the Kali Yuga. According to Hindu cosmology, life in the universe is created, destroyed once every 4.1 to 8.2 billion years, which is...
  
   up to 16,000 Yugas or Kalpas, and the height of the "Shades" is from half a Yojana
  Yojana
  A Yojana is a Vedic measure of distance used in ancient India. The exact measurement is disputed amongst scholars with distances being given between 6 to 15 kilometers ....
  
   up to 16,000 Yojanas (where a Yojana measures from five and a half to ten miles). Esoteric Philosophy teaches that though for the Egos for the time being, everything or everyone preserves its form (as in a dream), yet as Rupadhatu is a purely mental world, and a state, the Egos themselves have no form outside their own consciousness. Esotericism divides this world into seven Dhyanas
  Dhyāna in Buddhism
  Dhyāna in Sanskrit or jhāna in Pāli can refer to either meditation or meditative states. Equivalent terms are "Chán" in modern Chinese, "Zen" in Japanese, "Seon" in Korean, "Thien" in Vietnamese, and "Samten" in Tibetan....
  
  , "regions", or states of contemplation, which are not localities but mental representations of these.

• Arupaloka (or arupadhatu) is a world that is again divided into seven Dhyanas, still more abstract and formless, for this "World" is without any form or desire
  Tanha
  ' or ' literally means "thirst," and is a synonym for "desire" or "craving," traditionally juxtaposed with upekkha .Synonyms:*愛 Cn: ài; Vi: ái...
  
   whatever. It is the highest world of the post-mortem Trailokya; and as it is the abode of those who are almost ready for Nirvana
  Nirvana
  Nirvāṇa ; ) is a central concept in Indian religions. In sramanic thought, it is the state of being free from suffering. In Hindu philosophy, it is the union with the Supreme being through moksha...
  
  , and is, in fact, the very threshold of the Nirvanic state, it stands to reason that in Anupadhatu (or Arupavachara) there can be neither form nor sensation, nor any feeling connected with our three dimensional Universe
  Universe
  The Universe is commonly defined as the totality of everything that exists, including all matter and energy, the planets, stars, galaxies, and the contents of intergalactic space. Definitions and usage vary and similar terms include the cosmos, the world and nature...
  
  .

Sources

• Berzin, Alexander (March 6, 2008). Berzin Archives Glossary. Retrieved Sunday July 13, 2008 from "Berzin Archives" at http://www.berzinarchives.com/web/en/about/glossary/glossary_tibetan.html.

• Blavatsky, H.P. (1892). Theosophical Glossary. London: Theosophical Publishing Society. Retrieved 2008-07-14 from "The Theosophical Glossary (United Lodge of Theosophists, Phoenix, Arizona)" at http://theosophicalglossary.net/.

• Fischer-Schreiber, Ingrid, Franz-Karl Ehrhard, Michael S. Diener and Michael H. Kohn (trans.) (1991). The Shambhala Dictionary of Buddhism and Zen. Boston: Shambhala Publications. ISBN 0-87773-520-4.

• Monier-Williams, Monier
  Monier Monier-Williams
  Sir Monier Monier-Williams, KCIE was the second Boden Professor of Sanskrit at Oxford University, England...
  
   (1899, 1964). A Sanskrit-English Dictionary. London: Oxford University Press. ISBN 0-19-864308-X. Retrieved 2008-07-13 from "Cologne University" at http://www.sanskrit-lexicon.uni-koeln.de/scans/MWScan/index.php?sfx=pdf.

• Purucker, G. de (ed.-in-chief) (1999). Encyclopedic Theosophical Glossary: A Resource on Theosophy. Theosophical University Press. Retrieved from "The Theosophical Society" at http://www.theosociety.org/pasadena/etgloss/etg-hp.htm.

• Rhys Davids, T.W. & William Stede (eds.) (1921-5). The Pali Text Society’s Pali–English Dictionary. Chipstead: Pali Text Society
  Pali Text Society
  The Pali Text Society was founded in 1881 by T.W. Rhys Davids "to foster and promote the study of Pali texts".Pali is the language in which the texts of the Theravada school of Buddhism is preserved...
  
  . Retrieved 2008-07-13 from "U. Chicago" at http://dsal.uchicago.edu/dictionaries/pali/.

External links

• Bullitt, John T. (2005). The Thirty-one Planes of Existence. Retrieved 2007-04-30 from "Access to Insight" at http://www.accesstoinsight.org/ptf/dhamma/sagga/loka.html.