What is SLD?

SLD stands for Second Level Domain, which is a lower level domain in the Domain Name System hierarchy below the TLD. In example.com “.com” is the Top Level Domain and “example” is the Second Level Domain. SLDs refer to the organization or the individual that registered the domain name. Some registrars have introduced a second level hierarchy to the top-level domain, so that it indicates what kind of entity is intended to use it (.co.uk – intended for businesses based in the UK; .org.uk – non-profit organizations; .ac.uk – British academic institutions; .sch.uk – only for schools located in the UK and so on).