
1) Ancient Egyptian religion 2) Solar deity
Found on
https://www.crosswordclues.com/clue/atenism

Atenism, or the Amarna heresy, refers to the religious changes associated with the eighteenth dynasty Pharaoh Amenhotep IV, better known under his adopted name, Akhenaten. In the 14th century BC Atenism was Egypt`s state religion for around 20 years, before subsequent rulers returned to the traditional gods and the Pharaohs associated with Atenis....
Found on
http://en.wikipedia.org/wiki/Atenism

Atenism was a form of sun-worship practised in ancient Egypt around 14 BC.
Found on
http://www.probertencyclopaedia.com/browse/AA1.HTM
No exact match found.