The Mahatma reference article from the English Wikipedia on 24-Apr-2004
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Mahatma

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Mahatma is Sanskrit for "Great Soul." This epithet is widely applied to people like Mohandas Karamchand Gandhi (who was so qualified by Rabindranath Tagore) and is used to refer to adepts or liberated souls.

The word was popularised in theosophical literature in the late 19th century when Madame Helena P. Blavatsky, one of the founders of the Theosophical Society, claimed that her teachers were adepts or Mahatmas who reside in Tibet.

The Mahatmas are not disembodied beings, but people involved in overseeing the growth of individuals and the development of civilisations.