When you type in a domain name into an internet browser a website usually appears or the search results for what you typed. A domain name is similar to a license plate on a motor vehicle, in that it is a group of letters and or numbers that are registered with an authority and owned by someone.

A domain name can be purchased and then used for many domain name services (DNS) the most common being the address of a website eg www.cybernetny.com or for email eg. webmaster@cybernetny.com

There are top level domain names (TLD’s) and sub-domains:
eg cybernetny.com is a TLD
email.cybernetny.com is a sub domain

Domain names are sold as an annual subscription and registered with the Internet Corporation for Assigned Names and Numbers – ICANN  by official Registrars