A fully qualified domain name (FQDN) is a domain name that is completely specified with all labels in the hierarchy of the DNS, having no parts omitted. Labels in the Domain Name System are case-insensitive, and may therefore be written in any desired capitalization method, but most commonly domain names are written in lowercase in technical contexts.
A domain name can be used for a variety of purposes. Many people who are not ready for a website simply register the domain name of their choice to ensure it doesn’t get snatched up by anyone else. They may use it to create a professionally branded email address, or as a Web address that can point customers to an alternate online presence, such as their social media page, if they don’t yet have a website.
Domain names can be used in a number of ways. Direct visitors to your website’s home page or use complementary domains to send them to specific areas of your website ( e.g. yourcompany.jobs for a careers page). Or, forward a custom domain to an existing social media account, like your Twitter profile or Periscope channel. With a domain name you can even set up custom email addresses like email@example.com, which can be used to conduct business or communicate with your followers. More.