A couple of days ago, I was asked by a buddy of mine (a bit of a car buff), what the plural of Prius was. Hmm, said I, I didn't officially know. I would have said "Priuses", in its anglicised form. Why not Prii?, he asked. Well, I countered, take a common example, found all over the web - the online forum. We don't talk about two or more "fora" as it should be, given the Latin root word. Instead, we talk about "forums" - we've just anglicised the root word. So I thought Priuses would be the commonly accepted, official plural. Apparently not.
I have since found out that Toyota held a 'plebiscite', if you like. Toyota asked what the public thought the plural of Prius should be and counted the votes. "Prii" came out tops and on the 20th February 2011 the mighty Toyota corporation announced that "Prii" was the official plural of Prius. Think I'll be sticking with Priuses. Sounds better and less pretentious.