Any site at the time of creation is hosted on the server of one hosting company or another, which provides disk space for its storage. Each server, like any other computer, has its own IP address, which consists of a combination of numbers. Searching for sites by IP-address is extremely inconvenient, since hundreds of different web resources can be found on one server.
To identify and quickly find a site on the Internet, use the domain name (name or address of the site), which can be seen in the address bar (for example, site-town.com). Each domain consists of a unique site name (site-town) and a domain zone (.com).
The domain zone (or first - level domain) indicates the country to which the site belongs (.ru - Russia, .us - USA, .de - Germany, .ca - Canada), or by activity type (.info - for information sites,. org - for non-commercial organizations, .com - for commercial sites, but now it is available for unlimited registration, .net - initially for companies dealing with the Internet, but currently used for general purposes, .edu - for educational institutions) .
The part of the domain name that stands before the dot (ie before the domain zone) is called the second-level domain name. This is the unique name of the site. This type is paid, but it is the use of a second-level domain name in a certain zone (for example, site-town.com, telecasting.ru) is the most common and popular among website developers due to a shorter name, which means easier storage by users, and better ranking in the search engines.
The third-level domain is a subdomain of a second-level domain name and is separated from it by a dot. This type is mostly free, but has a number of drawbacks compared to the second-level name.