This is just a little riff on what might have been, but wasn't:

Let's say Cambodia did derive from a word that meant 'land of the gum trees,' then we could modernize the name and call it Gumbodia.

But thanks, hibernicus, for the more correct explanation.
And I enjoyed reading and thinking about your obscure fact. It has been very, very long since I studied French; I have forgotten most of what I'd once learned. But, based on what you have written, L'Angleterre and L'Allemagne (not sure of spellings) would both be feminine, yes?