The distinction in English might be more in "new" versus "used". And yes, that is inconsistent, you would think "new" versus "old" and "used" versus "unused". But alas :)
As in, a product that was manufactured, kept in its original packaging, and "unopened and unused".
(Although there's some allowances for the vendor to test because you don't want to buy something DOA.)
(Although I won't get too angry for someone saying "brand new." "New old stock" is kind of an obscure term that you don't come across unless you're the kind of person who cares about that kind of thing.)
