The dotted decimal notation system was difficult to remember, & hence a new IP addressing system using words was evolved. In this system, an address such as www.amazon.com is called a domain name. Domain names are sets of words that are assigned to specific IP addresses, & these names can have two or more word groups separated by periods. Domain names are formed by the rules and procedures of 'domain name system'. The extreme right part of the domain name is the most general, & each part of it becomes more specific as we move to the left from right. As an example, the domain name www.amazon.com contains 3 parts separated by periods. Starting at the right, the name 'com' indicates that the computer belongs to a company, the company is identified by the name 'amazon', & the word 'www' indicates that the computer is running software that makes it a part of the 'World Wide Web'.
Domain names are organized in subdomains or subordinate levels of DNS root domain, which is nameless. The rightmost part of the domain name is called a "top level domain",which include generic top level domains, such as com, edu, gov, net, info, mill, biz, name, pro, int, & org and the country code top level domains, such as uk, us, ca, au, & de. The Internet Corporation for Assigned Names & Numbers (ICANN) is responsible for managing domain names, & coordinating with the IP address registrars.