A domain name is a memorable phrase used to access your website, often "yourbusinessname.com".
Every computer connected to the Internet has a long string of unique numbers used to identify
itself called an "IP address". Without a domain name, you would need to remember the IP address in
order to view a website.
Domain names are purchased using a "registrar" which acts like a phonebook. When someone types in
your domain name, behind the scenes your registrar will look up your domain for them and return
your IP address back. Their computer will then know where to find your website.