A subdomain is a web address, that is under a main, or a root domain. An illustration is something.domain.com, in which domain.com is the main domain address, while "something" is the subdomain below it. Every single subdomain can have its own website and records i.e. aside from employing the domain name as a part of the whole web address, a subdomain can be entirely independent and even hosted by a separate service provider. Employing a subdomain can be extremely handy if you'd like to have different web sites that are connected in some way. For instance, you may have a web-based store under the main domain along with a forum under a subdomain in order to offer means for your customers to ask questions and / or share thoughts regarding your products. The best thing about employing a subdomain as opposed to a subfolder is that the websites are going to be separated, so that you can update one of them or perform maintenance without affecting the other.