what is atman in Jainism, Buddhism and Hinduism?

comparison of terminology in Hinduism, Buddhism and Jainism of the word Atman

Existential self is known as Atman or soul in these religions.

From my understanding in Hinduism Atman is the individual soul that is connected to the world or universal or one soul (Brahman). Buddhists I think believe in Andaman - or no soul. Not sure what the Jainist perspective on it is though. hope this helps.

In Hinduism, the Atman is the soul or eternal self that reincarnates again and again. The speculations in the Upanishads conclude that the Atman is the same as the Brahman (transcendent reality above understanding).

The Buddha denied the existence of the Atman, and so used the term Andaman, or no-self. This is one of the basic principles of Buddhism. Nothing has a lasting self that endures. Everything is temporary and passes away. We don't have an eternal soul. In fact, we don't even have a differentiated self.

The beliefs of the Jains are similar to those of the Hindus. They believe that each of as has an Atman or divine soul, and we have the potential to achieve God-consciousness.

Hope this helps.