What is a third-level domain (host) name?
A domain name can be broken into multiple components. For example, the domain name, mydomain.com, actually consists of three distinct components: “mydomain” is referred to as a second-level domain name, “.” is the root, and “com” is known as the top-level domain (TLD). A third-level domain is a sub-domain of a second-level domain and precedes the name of the latter. In other words, anything.mydomain.com is a third-level domain name and “anything” is a subdomain of mydomain.com.
