ISO Country Code (ISO-3166) - The ISO 3166 code is a code set by the International Organization for Standardization (ISO) to identify each country. The 2-letter country ISO code (ISO-3166-2) is more widely used, particularly with regards to the country's top-level domain (ccTLD). However, the 3-letter country ISO code (ISO-3166-3) gives a better visual between the ISO code and the actual country name.
Continent Code - The continent code is a 2-letter code that identifies each continent.
ccTLD - The ccTLD is an Internet country code top-level domain reserved for a specific country.