In today's field of gaming, the humble mana bar has become nearly as widespread as the health bar. Everywhere from MMOs to flash games, to traditional turn-based RPGs, Mana exists as a finite consumable resource (often a blue bar) used to cast spells and/or abilities.
And yet, the biblical definition of mana has little to do with the term as it exists in modern-day vernacular.
Tolkien or Dungeons and Dragons are the usual culprits for widespread fantasy terms (dwarves come to mind), but neither Tolkien nor any version of Dungeons and Dragons make mention of mana (Tolkien downplayed magic in general, and D&D has traditionally used the concept of "spells per day"), so the origin of the term remains unknown to me.
So where or when did "Mana" first become used in this modern, videogame-inclined sense?
Best Answer
It's almost certainly derived from a pan-Polynesian idea of "that which makes something effective" - usually, what makes magic effective. "Mana" tends to travel in the company of the idea of "taboo", the complex of rules that distinguish something as sacred. Mana comes from obedience of taboo, from the performance of certain rites, from pleasing the spirits of ancestors, or from other sources, depending on the particular island whose mana/taboo complex you're studying. (Keesing's Kwaio Religion is probably the most readable account, and recommended reading - the Kwaio have a verb that's a cognate of "mana", and their practices revolve around satisfying ancestor spirits who can in turn "namana"-ize their descendants' activities, mundane and magical alike, so that they meet with success.)
Larry Niven is probably the writer who brought the idea into Western fantasy literature, as the Wikipedia article indicates, and it spread in that millieu during the 1970s.