The country module defines the concepts of country and subdivision and comes preloaded with the ISO 3166 list of countries and subdivisions thanks to the pycountry module.
A country is defined by the full name of the country, a code (the ISO country code made of two chars) and the list of subdivisions.
A subdivision is defined by a name, a code and a type (e.g, Capital City, Province, Emirate, etc)
A zip links a zip code of a country to a city.