Second-level and lower level domains Below the top-level domains in the domain name hierarchy are the second-level domain (SLD) names. These are the names directly to the left of .com, .net, and the other top-level domains. As an example, in the domain example.co.uk, co is the second-level domain.
second-level and lower level domains below the top-level domains in the domain name hierarchy are the second-level domain (sld) names these are the names directly to the left of com net and the other top-level domains as an example in the domain examplecouk co is the second-level domain