A subdomain is a website address, which is under a main, or a root domain name. An illustration is something.domain.com, in which domain.com is the main domain name, while "something" is the subdomain below it. Each and every subdomain can have its own site and records i.e. apart from employing the domain name as part of the whole web address, a subdomain can be fully independent and also hosted by a different company. Employing a subdomain can be quite handy if you wish to have different web sites that are associated in some way. As an example, you could have an online store under the main domain plus a forum under a subdomain in order to supply means for your customers to ask questions or share experiences concerning your products. The main advantage of employing a subdomain rather than a subfolder is that the web sites will be separated, so you're able to update one of them or perform maintenance not affecting the other.