What are second-level and third-level domain names?
The portion of the domain name that precedes the top-level domain is called the second-level domain name (for example, the “icann” in “icann.org”). There are also third-level domain names that appear before the second-level domain name and again are separated by a dot (for example, events.icann.org). Third-level domain names are also called sub-domains and are often used to categorize special sections of a website.
