Q From Caiti: My ears are still burning! Hear my crime! I used the term one another to someone. I was told that I am (apparently) the only English user on the planet who is not aware this term is for use among three or more people, and that each other is the correct term between two. How much of a faux pas is it, really? Is a firing squad at dawn too good for me? I have searched, in vain, for the answer.
A Be at peace. It is your critic who is wrong to force this view on you. There is some reason for it, though, since the belief has been widely held in the past. However, no modern writer on the language attempts to justify it, not even the sainted Fowler back in 1926.
It seems to have been one of those pedagogical assertions invented by eighteenth-century grammarians. It has been traced back to a 1785 grammar by a George N Ussher, though it was most widely and firmly promulgated by several writers in the following century, notably the American grammarian Goold Brown, in The Grammar of English Grammars, published in New York in 1851.
He was somewhat surprised to find that the rule was often broken, and commented that both Samuel Johnson and Noah Webster were guilty of getting it wrong (actually of using each other for more than two persons). These impeccably grammatical writers were not in error at all, of course, since there never has been any such rule in real life. It seems to have been invented according to some whim or mistaken belief, either by Mr Ussher or by one of his brethren. The Oxford English Dictionary has nearly 2000 examples of the phrase one another in various places. I can hardly claim to have inspected more than a few of them, but the evidence is clear that each other and one another were used interchangeably centuries before anyone attempted to place a formal restriction on their use. Here’s Shakespeare, in Henry VIII: “his mind and place Infecting one another, yea, reciprocally”.
Accept this gobbet of academic etymology with which to confound your opponent: historically one another is an abbreviation of the one the other and in that form was certainly used only of two people. The extension to more than two was a later development allied to its shift in form. So, if the pedant who thought up this artificial restriction had had his historical antennae properly tuned, you might now be hearing the rule the other way round.
Observe the rule if you wish, ignore it if you wish. If you choose the latter, you will have hundreds of the best writers from Shakespeare onwards on your side.