Bad Luck says "When you roll a dice, subtract one from the roll" (Or words to that effect). "Dice" is the wrong word in the context, it should be "die" since it is singular, but "dice" is plural - you can't say "a dice".
Technically, many people do! It's a linguistic standard in different places. And since these designers are in/from scattered cultures, it's possible somebody just put this one in and no one questioned it. They should probably change it to "die" anyway, since they're not doing "manoeuvre" or "armour" et al.
We've used "dice" in the singular since 1751: So I reckon we're good from a UKian perspective. I'll get back to you on the Armo(u)r issue!
Armor/Armour is OK (although ridiculous, and just Americans wanting to be different. I can live with either). However, "Dice" is a plural term. Just because someone used it wrong back in 1751 doesn't mean it was any more correct then than it is now. There *are* some plural terms that have been singularised over the years (e.g. "data" is plural, "datum" is the singular, but nobody uses that) but "roll a dice" if you're only talking about one just looks wrong and should be changed. Just my 2c.
A cube of cheese no larger than a die May bait the trap to catch a nibbling mie. Ambrose Bierce, The Devil's Dictionary.
