More like meta-cooking question, but I believe it fits here better than on travel stack.
Is there a historical reason for that - similar (for the sailors in XVI century) food from different exotic countries? Or do they have similar basis, like set of spices, flavors?
There are at least few different dishes (or even dish families) from different countries that western people call curry, even if they are not similar:
So, how to differentiate it all? Do all of those have something in common? Or is it just lingual lack of proper wording.