Looking at Wikipedia's Glossary of Buddhism, when it comes to the important word âtman, I am guessing that it was probably put there by someone who pulled it out of their arse. I am also guessing that the guy never heard of Yaska's hermeneutical work Nirukta which, by the way, predates Buddhism. The Nirukta is the oldest Indian treatise on etymology, philology and semantics.
This important text also happens to give the root terms of âtman which are √at (constant motion) and √ap (permeation). Âtman does not literally mean "self" or "I" or "ego." I hate to say this, but this is just more evidence of Westerners trying to force âtman into a mold they would much prefer—but is incorrect. Of three meanings Yaska gave âtman the third is the one for our purposes. It means the ultimate sentient principle or better, the animative principle (cetanatattva).
As far as âtman relates to Buddhism (attâ in Pali which comes from Prakrit)—staying clear of the sectarian doggie poop—âtman is not the bad boy. Throughout most of the Buddha's discourses such as the Samyutta-Nikaya, the negative âtman, this being anâtman, is used for a special purpose: We are to reject what is not the self or anâtman—not the âtman! We could also put it this way: The purport of anâtman is all identification with conditioned things such as the five grasping aggregates must be got rid of. The Buddha even tells his followers: "Abandon desire for whatever is anâtman" (SN 22:68).
Based on the correct meaning of âtman, which is the animative principle, it is not to be found in essentially conditioned and mortal things such as the five grasping aggregates. Neither is the Tathagata or nirvana.