1. What is a domain name?
A domain name is the name of a server or a network system on the Internet. There are no duplicate domain names in the world, and the domain name is unique. Technically, a domain name is just a method used to solve address mapping problems on the Internet. It can be said that it is just a technical term. However, since the Internet has become the Internet for people all over the world, domain names have naturally become a social science term.

2. What is the hierarchy of domain names?
Domain names are divided into top-level, second-level, and sub-domains.
There are several types of top layers, which are:
.com commercial organization or company
.org non-profit organizations, groups
.gov government departments
.mil Military Department
.net An institution or company that engages in Internet-related network services
.XX is a two-letter country code, such as .cn for China, .jp for Japan, and .uk for the UK.
.biz means business
.info general information service use
As an international top-level domain name, .tv was originally the country code top-level domain name of Tuvalu, a Pacific island country. Through an agreement with Tuvalu, DOTTV has become the exclusive registrar and registry for the .TV suffix.
.cc is an officially authorized domain name located in the Central Cocos Islands in the Indian Ocean, northwest of Australia. In the United States, .cc has become the third largest top-level domain name after .com and .net, and choosing to use a .cc domain name has become a trend.