This is both an EL&U question and a FL&U question, so I've double-posted accordingly to maximize visibility.
Here's the thing that struck me as odd today.
In English, we would say "his right arm." But we would also say "he has the right to do something."
In French, we would say "le bras droit." And we would say "Il a le droit de faire quelque chose."
So, given that the English "right" is not (so far as I can tell) in any way similar to the French "droit," how is it that they both happen to have these two disparate meanings in both languages? I'm inclined to say it's not a coincidence. How would that happen?