A domain name is a unique web address on the Internet, like www.example.com. Much like buying real estate in the physical world, when you register a domain name it becomes your property in the online world. No two domain names can be the same which means that if the domain name you want is already registered, you are unfortunately out of luck. Domain names can also have different domain extensions, or TLDs, attached to the end of it. For example, you may own www.example.com, however www.example.net may still be available.

Domain extensions are the letters that appear after your domain name. For instance, in www.example.com, .com is the extension. There are several to choose from and they typically represent a word - com represents the word "commercial", mobi is short for "mobile", and so on.