A domain name is the portion of a URL that is unique to a web site. For the URL "https://www.MichaelHaynes.com", the domain name is "MichaelHaynes.com".

Each domain name is registered to only one owner via a domain name registrar. Registrations expire after a pre-specified period of time, and must be re-registered beforehand (with any registrar), otherwise another could register the same domain name, and thereby obtain rights in that domain name.

Disputes can arise when someone registers a domain name that is confusingly similar to another's domain name, or to another's mark, particularly if the mark is famous.

The ICANN organization has promulgated a Domain Name Dispute Resolution Policy with which most registrars comply.