Domain - a special area on the Internet - a unit of administrative division of the World Wide Web. Symbolic names exist to identify domains. A common namespace operates within a system where domains are hierarchical.
Fully qualified domain name is the domain name itself and then the names of all domains to which it belongs. Domain names are separated by levels by dots. Domain zone - a "set" of domain names of a specific level included in any specific domain.
The following example can be given. https://msu.ru/ - portal of the Lomonosov Moscow State University. It is listed among all Russian Internet pages (zone ru). Within its framework, there are the websites of the Faculty of Public Administration - https://www.spa.msu.ru, the website of the Philological Faculty - https://www.philol.msu.ru, the website of the University Choir - https://choir.msu.ru / and many others (as you can see, everything is based on msu, which in turn is part of ru - the sphere of Russian domains).
With the development of the Internet, domains with “nice” and “understandable” names have become of great importance. All this despite the fact that the number of registered domains is approaching 200 million, and it has become extremely difficult to find a free domain name - specific, memorable, short. There is already a market for the resale of domain names. Organizations here that register domains, buy and sell them on the secondary market, place advertisements on officially registered domains … About a third of domestic sites do not contain any information. They are only needed to sell sponsored links.
It's worth noting that not all first-level domains are "country-specific". So, for example, there is aero - the area of sites about air transport, edu - educational pages, travel - resources dedicated to travel, xxx - adult entertainment, etc. In addition, there is already a trend towards “city orientation”. There is an idea to create top-level domains. MOSCOW and. MOSCOW (the project was supported by the government of the capital; the application is planned to be submitted in 2012).
