Typically known as a "domain within a domain", sub domains are individual Web addresses built upon a pre-existing domain name (such as clientname.yourhostingcompany.com). As a reseller, you will have the option of assigning sub domains to clients if they do not choose to have a domain name.
A sub-domain is very similar to Directory Aliasing (DIR Aliasing), except that instead of www.newdomain.com pointing to www.primary.com/newdomain, www.newdomain.primary.com will point to www.primary.com/newdomain. The difference is that you do not need another domain name. This allows you to select a sub-domain that will act as a prefix on your existing domain. For all sub-domains we will assign another IP address and directory in your domain to be used as the home directory of your sub-domain's web site. NOTE: Sub-domains are very popular in situations where a customer is hosting multiple applications under one domain, i.e. Web Hosting, Microsoft® SharePoint(tm), SQL, Microsoft® Exchange Server, etc. In this example, it would be advisable for the customer to have multiple sub-domains, i.e. www.mydomainname.com, spt.mydomainname.com, exchange.mydomainname.com, sql.mydomainname.com, etc. Web Album The Web Album is a web-based tool that allows you to create, manage, view and share your photos online. Simple and easy to use, the Web Album is available FREE on all our hosting plans.
A subdomain is a domain that is part of a larger domain name. DNS hierarchy consists of the root-level domain at the top, underneath which are the top?level domains, followed by second?level domains and finally sub?domains.
A sub domain is an address which operates just below your top level address. Sub domains are easy to remember addresses that serve as extensions of your top level domain name. A sub domain looks like this: anything.mydomain.com