A domain name is an easily readable and rememberable string that is entered into a browser web address bar in order to locate a computer on the internet hosting code and files representing a web application.
Domain names consist of 3 important parts.
The Top Level Domain (TLD)
Also known as the extension. An example would be .co.uk or .com.
The Second Level Domain (SLD)
The textual part of the name and would usually represent your business or organisation name.
The Sub Domain
Element of a domain name which is optional but has, since the beginning of the internet age become the norm to use www for. Recently many have dropped this part of the domain and just use the TLD and SLD parts of the domain (e.g. example.com)
To get a domain name for your business or organisation you need to set one up with a registrar. Registrars operate and manage Top Level Domains (TLD). In the UK the .co.uk domain name registrar is Nominet. There are many different Registrars offering many different TLD’s (.shop, .net, .com etc)
Usually, however, you do not register a domain directly with a TLD registrar. You use an domain registration agent (e.g. names.co.uk, 123-reg.co.uk etc).
When you want to register a domain name you would go to one of these domain registration agents websites and follow their standard proceedures for registering a domain. This consists of you entering the textual part of the domain you want to register, representing your business or organisation name (SLD) into a text box and choosing an extension (TLD) you want to use (e.g. co.uk, .com etc) from a dropdown list. On clicking search this registration agent website sends a lookup request in the background to the TLD registrar systems (a WHOIS request). If you the SLD text you’ve entered does not exist in their database already then you are free to proceed.
Registering a domain consists of you renting the right to exclusively use the domain for a period of time. This period of time is usually between 1 – 10 years. During this period of time that domain is under your control and you can setup websites or apps using it. At the end of your rental period you have the automatic right to renew your rental agreement. Should you choose to do so then another payment will be due to the registration agent and TLD registrar. If you choose not to renew a domain your control of it will eventually be released and other companies or organisations will be able to register it.
Domain names have records associated with them that you maintain (usually via a system provided by your domain registration agent) in order to setup websites, apps, mail on your domain. These are called DNS (Domain Name System) records. Take a look at our guide → What is DNS?