A Domain Name is the way of identifying the location of a certain site on the internet.
I find the best way to understand is with an example. So, let’s take Wiser Websites.
wiserwebsites.com
This is known as our link address. However, it is made up of the different types of domains. Wiser websites is our Domain Name. It is the title of our company. The .com is known as the Top-Level Domain. A Top-Level Domain is something every site/link must have. Some examples are .com, .co.uk, .org, .net and many others.
The specific Domain name tends to be the title of the site. So, if it is you companies home page it would tend to be your companies’ name. But if it was a site where you answered a question the question would tend to be the Domain Name. It is an incite as to what you will find on the site.