A subdomain is a web address, that's under a main, or a root domain. An example is something.domain.com, in which domain.com is the main domain, while "something" is the subdomain below it. Every single subdomain can have its own site and records i.e. aside from employing the domain name as a part of the whole web address, a subdomain can be fully independent and also hosted by a separate service provider. Employing a subdomain can be extremely practical if you'd like to have different websites that are associated in some way. As an example, you may have an on-line store under the main domain along with a forum under a subdomain so as to provide means for your customers to ask questions or share views regarding your products. The benefit of employing a subdomain as opposed to a subfolder is that the websites will be separated, so you can update one of them or perform maintenance without affecting the other.