The word altruism was popularised (and possibly coined) by the French philosopher Auguste Comte (1798-1857) c.?1830 in French, as altruisme, as an antonym of egoism. He derived it from the Italian altrui, which in turn was derived from Latin alteri, meaning “other people” or “somebody else”. Altruism may be considered a synonym of selflessness, the opposite of self-centeredness.
My current inadequately informed — (as always, I reserve the right to revise) — hypothesis is that the concept of altruism was coined by a quantlocked positivist, stuck in a wordworld of defined objects, composed of nothing but objects, comprised by nothing real. In this objective world one can only act selfishly or selflessly for the sake of exterior others, with no enveloping being among or beyond.