A fully qualified domain name (FQDN) consists of a top-level domain and the domain itself. For example, an FQDN for google is google - the domain and .com - the top-level domain.
In Domain Name System (DNS) a domain name serves as easy to remember name instead of the Internet Protocol addresses (IP Address) used by internet connections around the world. This allows users to easily identify the website address, rather than the IP address which is in the format of 127.0.0.1.
A nameserver is a hosting server that is typically operated by your hosting company. Nameservers hold records of where to point your domain, and these nameservers are set against the domain name record.
When nameservers are updated, and a user visits the website, the new nameservers are loaded, and the current IP address of where the website is located is found. This address can be stored in DNS cache on your computer; we recommend waiting around 40 minutes when changing nameservers.
Top-level domains (TLDs) are marked by the letters to the right of the dot in the domain. Countries are assigned domain names, such as .co.uk for the United Kingdom and .com is associated with the United States.
Registrars are the authorities that assign domain names and can register them under InterNIC, an ICANN service that determines the uniqueness of domain names on the Internet, and others such as Nominet in the United Kingdom.
If you register a domain name, for example, "example.com" you could purchase website hosting and point the domain name to it by setting the nameservers and host a website or email service.
If you build your website on a web host and register a domain name, your website will be visible to people on the web.
Many website hosting companies also allow you to register and purchase domain names, so you can easily manage the domain with the name and the entire website in one account.