I'm not clear if there's a distinction between these two.
Under the section for Ether, on the Elements page, the wiki states, "It is artificial magical energy that forms the basis of modern magecraft, although it did not exist during the Age of Gods."
Under the section for Mechanisms, on the Magical Energy page, the wiki states, "Ether is not a form of magical energy, but instead something else entirely."
Any insight is appreciated.