The word atone was first used as a noun in 1559, but it existed as a verb for four years before that, first showing up in a translation by writer William Waterman with a definition of "be unified" or "in harmony", the idea being that once you atoned for your sins, you could be at one with the universe and God, which is where the word comes from. At one as a phrase signifying that state of concord has been around since the thirteenth century, and was increasingly combined after Waterman did it first. Through Old English and Proto-Germanic, at is derived from the Proto-Indo-European reconstruction hed, which could also mean "near". One, by way of Old English an and Proto-Germanic ainaz, traces to PIE oynos, still with the same meaning.
Adam Aleksic, an incoming freshman at Harvard University, has been described as the internet's sixth most famous etymologist. He has disturbing interests in linguistics, vexillology, geography, board games, limericks, and law, and he loves writing about himself in the third person.
The Etymology Nerd