grammatical number - Is -1 followed by a singular or plural noun?

Do we say "-1 thing" or "-1 things"?

I am interested in both

two things minus one thing(s)

and

minus/negative one thing(s)

Answer

A few elements of response:

1. authority: as mentioned by Cawas, there is not ultimate authority on the English language, and while there are a number of references, I have not been able to identify a solid consensus on the subject.




2. Usage: It is fairly difficult to check this due to the possible misunderstanding between "(minus one) thing" and "minus (one thing)", assuming that these are two separate cases, an assumption I would tend to disagree with.
   However, searching for "minus one dollar" -infinity on Google returns 254,000 results while "minus one dollars" -infinity returns only 7 results. The difference is significant enough to consider that regardless of any possible confusion as suggested above, minus one should be followed by the singular, at least in this case. ("-infinity" is added to the search phrase to exclude the expression "infinity minus one dollar").
   "minus three dollars" is significantly more common than "minus three dollar", suggesting that "minus" itself does not affect the rules of the plural/singular following numbers.





3. Logic: "minus one" is not an actual quantity in the physical universe. "Minus one" is only an abstraction which refers to the action of subtracting one of anything. Rather that saying "whenever you have apples, remove one apple" we say "minus one apple". It follows that "(minus one) thing" and "minus (one thing)" are actually equivalent.

Barring incontrovertible evidence to the contrary, I would say that it is safe to use the singular following "minus one".