A domain name is a name used to identify a web site on the Internet.
When someone types your site’s domain name into a web browser like Chrome or Firefox, the web browser uses DNS to locate where that website is hosted (see web hosting) and loads the pages associated with that web site.
Acquiring a good domain name is key to the success of your site. You want to make it as easy as possible for your customers / audience to get to your site, so getting a domain name that matches, or closely matches your company / blog name is important.
Domain names can be purchased through a domain registrar who is responsible for telling the Internet where you site is located.