A subdomain is a website address, that is under a main, or a root domain name. 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 site and records i.e. aside from using the domain name as part of the whole web address, a subdomain can be completely independent and also hosted by a different company. Employing a subdomain can be very beneficial if you'd like to have different 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 clients to ask questions and share thoughts concerning your products. The advantage of using a subdomain instead of a subfolder is that the web sites will be separated, so you are able to update one of them or perform maintenance not affecting the other.