Country code Top Level Domains (ccTLDs) are top-level two-letter domains, national domain zones (UA - Ukraine, KZ - Kazakhstan, BY - Belarus, US - USA, FR - France, JP - Japan, IN -India and so on). These domains are appointed by international IANA (Internet Assigned Numbers Authority) organization according to codes of countries and territories.

On an international agreement, each country has specific two-letter code mark — two-letter national ISO code.