A Second-Level Domain (SLD) is the portion of a domain name that appears directly to the left of the TLD. In 'example.com', 'example' is the SLD. The SLD is typically the most important part of a domain for branding, as it's the unique identifier chosen by the registrant. In some ccTLDs, there are second-level domains used for categorization, like .co.uk (commercial UK) or .ac.uk (academic UK).
FAQ
What is a second-level domain?
The SLD is the main part of a domain name you choose — 'mycompany' in 'mycompany.com'. It's the core of your brand's web identity.