A subdomain is a website url, which 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. Each and every subdomain can have its own site and records i.e. apart from employing the domain name as a part of the whole web address, a subdomain can be entirely independent and even hosted by a different company. Using a subdomain could be very practical if you'd like to have different web sites which are related in some way. For instance, you may have an online store under the main domain as well as a forum under a subdomain in order to supply means for your clients to ask questions or share thoughts regarding your products. The benefit of employing a subdomain rather than a subfolder is that the web sites are going to be separated, so you are able to update one of them or perform maintenance without affecting the other.