A subdomain is a website address, that's under a main, or a root domain name. One example is something.domain.com, where 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 completely independent and also hosted by a different provider. Employing a subdomain can be quite beneficial if you wish to have different sites that are associated in some way. For instance, you can have a web-based store under the main domain and a forum under a subdomain so as to provide means for your clients to ask questions and / or share thoughts about your products. The advantage of employing a subdomain as opposed to a subfolder is that the sites are going to be separated, so you're able to update one of them or perform maintenance without affecting the other.