Second Level Domain Name Law and Legal Definition

In the Domain Name System (DNS) hierarchy, a second-level domain (SLD) is a domain that is directly below a top-level domain (TLD). SLD is the organization that registers the domain name with a domain name registrar. Some domain name registries introduce a second-level hierarchy to a TLD that indicates the type of organization intended to register an SLD under it. The SLD is the portion of a domain name that is owned by the domain name registrant. The combination of a TLD and SLD name is unique. There can only be one TLD, even though there can be multiple SLDs.