Your domain name is your unique identity on the internet. The most common domain names end with .com, such as "microsoft.com" and "IBM.com". There are also other domain name extensions, such as .net, .org, .biz, .info, .us, and many more.
A domain name is made up of two parts: the second-level domain (SLD) and the top-level domain (TLD). For example, in the domain name "YourBusinessName.com", "YourBusinessName" is the SLD and ".com" is the TLD. Technically, a domain name points to a domain, rather than a specific web server or machine on the internet.
Additionally, the name "www.YourBusinessName.com" is not actually a domain name, but rather a subdomain that points to a specific computer named "www" within the domain "YourBusinessName.com".