I just ran across this somewhat funny set of videos for the plural of Prius. Videos: James Lipton tries to find plural of Prius in Toyota 'Wordliness' series — Autoblog I hope the link works correctly. Mike
In Latin, Prius is not a noun, but an adjective. The plural is Priora. In English, Prius is now a proper noun, so Priuses is never wrong. Using Prii is a back-reference to Latin, where that would be an error.
A joke. Q: What's the plural of Lexus? A: Nobody knows. Nobody has been able to afford more than one Lexus.
According to Toyota, the plural of Prius is Prius. Since they coined the use of Prius as a proper noun, they get to coin the plural as well. Tom
Well 'round these parts we do have more than one Lexi and are going to buy a second Prii. Cactus --> Cacti Octopus --> Octopi Lexus --> Lexi Prius --> Prii
I always use Priuses. I don't have any real heartburn with "Pree-eye", since anyone who has ever read my posts knows for sure that I'm not en english major, but "Prii" just seems a little too 'cutesy' for me. Toyota may get to pick what they call Priuses, but I get to pick what I call them.
I use and voted for Priuses but I am starting to like Prium. The image doesn't come out right. Link: http://www.roogio.com/images/Detroit-2011-Girls-Toyota-Prius-booth.jpg