Use the indefinite article.
(i.e "an arch" instead of "the arch".
This should give you "une arche".)
> to complicate the matter, some words can be masculin or feminin
> depending on the context!
Please give some examples. Do you mean natural gender? By this I mean
using a different word for male and female instances of an animal,
such as the use of the word "drake" in english for a male, and the
word "duck" for a female or indeterminate instance of the animal.
Many of these distinctions are no longer commonly used in english.
Farmers and vets have their own terms for animals of various sexes
(male, female, neutered).
