Meaning

originBorrowed from Māori mana, ultimately from Proto-Polynesian *mana, from Proto-Oceanic *mana. The use of "mana" for "magical energy" in role-playing games originated from Larry Niven, when he wrote the short story, "Not Long Before the End", in 1969. It was later popularised by his The Magic Goes Away setting.

Etymology from Wiktionary, CC BY-SA 3.0