Multiple domain capability gives you the ability to use several different domains on the same website account. This capability is devided into two catagories, domain parking and domain mapping.
Domain Parking allows you to overlap domains on your primary domain. Essentially you can give your website different names and all domain names will show your website. Domain Mapping (also called pointing) goes one step further allowing you to point domains to different directories in your account (not available on some account types, please check with us to confirm). This gives you the ability to create multiple websites with a single account and is not usually offered by other ISPs.
Another class of domains is called subdomains. Subdomains are domains in the form of subname.yourdomain.com and are often used as navigational aids, sub-accounts, or to reach specific directories quickly on the web.