Wiktionary
n. (context Buddhism English) The doctrine that there is no transcendental ego or soul; that the perceived true self is an illusion. Corresponds to the Hinayana or Theravada Buddhist doctrine of anatta.
Wikipedia
Anātman in Sanskrit means that "which is different from atman" or "non-self". In Hinduism, the former definition is found in some texts, while in Buddhism, anātman or anattā means non-self.
Usage examples of "anatman".
And against the Atman tradition, the Anatman doctrine was wielded with much polemical force: in place of substance, flux.
If there is indeed Buddha-nature, it would not leave itself without a witness in other cultures, other places, others times: and in the ears of sensitive men and women, it seems to have whispered the equivalent of "Mahatman" much more often than "anatman.
So, the Buddha said there isn't any atman: he taught the doctrine of anatman, or nonself.