A sub-domain is a domain that is located under another domain in the hierarchy. In common parlance, therefore, most domains referred to are actually domains on the third level or further down. A domain that is located directly under the Top- Level Domain is colloquially referred to as a Second-Level Domain or just a domain. For example, webland.ch. is a sub-domain of the Top-Level Domain ch. or www.webland.ch. is a sub-domain of webland.ch.