subject: What Are Second Level And Lower Level Domains [print this page] A domain name signifies authority on the Internet and is based on what is called the Domain Name System (DNS). Domain names exist for addressing purposes. This is so you will be directed to the correct website. However, there are different parts to a domain name that you need to be knowledgeable about. It isn't just a bunch of dots, letters, and dashes. Each part has a different function.
To understand this more in depth, it is important to understand what a top level domain (TLD) is. It is simply the extension at the end of your website address. It is the .com, .org, .net, or .info that you may have placed at the end of your domain. The invisible dot being referred to would be to the right of that. For example, .com would appear .com. if the dot were visible.
Below the top-level domains in the domain name hierarchy are the second-level domain (SLD) names. These are the names directly to the left of .com, .net, and the other top-level domains. As an example, in the domain mydomainchallenge.com mydomainchallenge is the second-level domain. If I was to put a dot in the middle of that mydomain.challenge then my domain would be a third level domain and so on.
The second level domain consists of the company name in most cases. That's unless that name is already being used for someone's domain. It can more or less be whatever you want as long as it is available.
It may be worth noting that the domain name system contains an even higher level of domain than the top-level domain. The highest level is the root domain, which would be represented by a single dot (just as in many hierarchical file systems, a root directory is represented by a "/") if it were ever used. If the dot for the root domain were shown in the URL, it would be to the right of the top-level domain name. However, the dot is assumed to be there, but never shown.
Another thing that you need to be aware of the difference between a URL and a domain name. Something like www.mydomain.com is a domain name. A URL would appear as this: http: //www.mydomain.com/index.html. The good thing about this is that both the URL and the domain share the same IP address and will go to the same place. So if you type in www.mydomain.com, it will take you to http: //www.mydomain.com/index.html. You'll usually notice this in the address bar.
So now you know about top-level domains, second-level and lower level domains, the root domain, and the difference between a domain and a URL. Many do not realize that there are so many different parts to their domain name and how important each part is in directing individuals to a website. Each part is also very important to the overall organization of the Internet. Without such a system put in place, the Internet would be a giant cluster of chaos. As busy as it is, chaos would certainly not be a good thing.
