SLD (Second Level Domain Names)Second Level Domains (SLDs) are subdivisions of a TLD. These further define an organisations activity within the TLD.
Examples of SLDs governed by Nominet, all belonging to the United Kingdom TLD (.uk) are:
for commercial enterprises (the largest SLD in the UK)
for personal domains
for non-commercial organisations
for registered company names only
for Internet Service Providers
These are commonly known as ccSLDs (country code second level domain) – ie. the SLD is attributed to a country code TLD.