Pfranz, you see virus as fourth-declension plural?Nope, I don't see anything at the moment. All my Latin books are currently in boxes awaiting transfer to the same bookcase, but at a different location ...
My (ever-faulty) memory just has this thing about single syllable stems in the fourth declension and how the plurals were sometime formed. Virus seems to fit. IF it's fourth.
Jenet may well be right, and I'm not arguing!
Aha, found what I was looking for on the net:
Manus -us, nf, hand
Case Singular Plural
Nominative manus manus
Genitive manus manuum
Dative manui,manu manibus, (manubus)
Accusative manum manus
Ablative manu manibus, (manubus)
Locative mani manibus, (manubus)
Vocative manus manus
This formation holds for both masculine and feminine nouns. For neuter nouns, as Jenet says, the form is
Cornu, -us, nn, horn
Case Singular Plural
Nominative cornu cornua
Genitive cornus cornuum
Dative cornu cornibus
Accusative cornu cornua
Ablative cornu cornibus
Locative ? cornibus
Vocative cornu cornua
None of which, of course, supports my impression, because I still don't know if virus was 4th declension! However, I'll lay odds that if it is it is masculine or feminine. If it's second, of course, it's mostly likely to be masculine, although there were a few feminine examples.
Found this, though, in Notre Dame's on line Latin Dictionary. It's probably as authorative as we're going to get:
virus -i n. [slimy liquid , slime; poison, esp. of snakes, venom; any harsh taste or smell].
So it's second dec, and it's masculine more likely than not. Phew!
