The domain name system. The DNS server.
The Domain Name System (DNS) is a hierarchical and decentralized naming system for computers, services, or other resources connected to the Internet or a private network.
It associates various information with domain names assigned to each of the participating entities.
It is most commonly used to obtain an IP address by hostname, obtain mail routing information and / or service nodes for protocols in a domain.
Domain name is part of the URL for a resource on the internet.
For example, nis.edu.kz, bzfar.org, vk.com
In nis.edu.kz:
kz - top level domain name
edu - second level domain name
nis - third level domain name or subdomain
A top level domain (TLD) is the portion of the domain that appears on the right side of the domain name after the dot, such as com, org, or net.
DNS server is an internet service that translates website domain names into IP addresses.
All websites have equivalent IP addresses.
Why a company use a domain name instead of an IP Address for their website?
Domain names are easier to remember
You can change the IP address without the user noticing
You can host several websites on one IP address