Atman, (Sanskrit “self breath”) as a term has several meanings, in the profoundest sense means self, pure consciousness, the “universal selfhood” that is the same in each individual entity whether organic or inorganic. It is a philosophical topic.
In Hinduism, when spelled was a capitalized “A”, it means the Great Self, identifiable with Brahma, the Creator. However, when not capitalized, atman has the quantity of being individual egos, or invisible “Higher Selves.” It is one of the main principles of Hinduism.
Atman can be translated as “Soul,” which is not designated as body, mind, or even thought because these designations are conditions that prevent the Soul’s union with God. In the Upanishads it is stated, “The Self, smaller than small, greater than great, is hidden in the heart of the creature;” and “In the beginning there was the Self.”
In Buddhism, Atman does not exist whereas in Hinduism it does. Hindus believe in Atman, as dual or not dual.