SLD

Alternatively called 2LD, a SLD or Second-Level Domain is the domain that is directly below the TLD (Top-Level Domain). For example, with "computerhope.com," "computerhope" is the second-level domain of the ".com" domain. With a domain name like "google.co.uk," the ".co" is the second-level domain of ".uk" and "google" would be considered the third-level domain.

Computer acronyms, Domain, Network terms, Subdomain, TLA, TLD