Several options: (a) It has no plural, because it's not a noun (or an adjective or verb). It's an adverb, meaning "formerly, previously". So, incidentally, if the marketing wonks were shooting for something "forward" or "first" or "preeminent" they blew it. (b) If you decide that, in this case, it's a 2nd declension noun, then the plural is indeed "prii". (c) On the other hand, it could be 4th declension, in which case the plural is prius, but with a long "u": PREE-ooss. (d) Or you could decide this is silly, it's English, and the plural is "priuses".
And by the way, it's "one Volvo, two or more Volvimus" %^).
no subject
(a) It has no plural, because it's not a noun (or an adjective or verb). It's an adverb, meaning "formerly, previously". So, incidentally, if the marketing wonks were shooting for something "forward" or "first" or "preeminent" they blew it.
(b) If you decide that, in this case, it's a 2nd declension noun, then the plural is indeed "prii".
(c) On the other hand, it could be 4th declension, in which case the plural is prius, but with a long "u": PREE-ooss.
(d) Or you could decide this is silly, it's English, and the plural is "priuses".
And by the way, it's "one Volvo, two or more Volvimus" %^).