The word “domain” has a number of meanings, including the geopolitical definition of a specified region or territory under the control of a particular ruler or regime. Given the context from which the question was posted – in effect, an accompanying question referring to social networking and the internet – it will be assumed that the definition of “domain” being sought is that pertinent to computer networking. Given that assumption, “domain” refers to the registered website or URL (Universal Resource Locator) to which one is entitled by virtue of it having been registered. In short, the domain is the internet address for a particular website. An example would be www.eNotes.com. Domain addresses are generally registered with the Internet Corporation for Assigned Names and Numbers (ICANN), a privately-owned company that emerged as an early and major service provider for those looking to secure unique addresses on the internet. Additional companies have since emerged to help individuals, businesses and organizations register their preferred domains.