It's not virii because virii is the plural of the non-existent word "virius" (declined as filius). And it can't be viri, either, because viri is vir nominative plural. That's the exhaustive explanation.
The more meaningful explanation is that virus had no plural in the Latin for the same reason that love, information and water (usually) have no plurals in English. Virus originally meant filth, venom or poison, and so a mass noun, not a count noun.
So viruses is correct, either because it's the standard rule for the formation of English plurals, because all the other possibilities are exhausted, or because the OED says so, whichever seems most convincing.
Slashdot Mirror
"Can machines think?" != "Can machines manage OCR?"
Yes, but we're dependent on the Morlocks for all of our technology.
It's not virii because virii is the plural of the non-existent word "virius" (declined as filius). And it can't be viri, either, because viri is vir nominative plural. That's the exhaustive explanation. The more meaningful explanation is that virus had no plural in the Latin for the same reason that love, information and water (usually) have no plurals in English. Virus originally meant filth, venom or poison, and so a mass noun, not a count noun. So viruses is correct, either because it's the standard rule for the formation of English plurals, because all the other possibilities are exhausted, or because the OED says so, whichever seems most convincing.
It's not "virii".
I suppose the term "Mac Daddy" would be inappropriate here.