Second-Level Domain (SLD)
The label directly left of the TLD — the "example" in example.com — the part you actually register.
Published on June 22, 2026By Namefi Team
- glossary
A second-level domain (SLD) is the label immediately to the left of the TLD — the example in example.com. It is the part you actually register through a registrar, and combined with the TLD it forms the registrable name that the registry records against a registrant. Everything to the left of the SLD — www, blog, app — is a subdomain you control yourself; everything to the right is the public suffix. Because the SLD+TLD pair is the unit of ownership, it is exactly what Namefi tokenizes: the registrable name becomes a wallet-controlled asset, while subdomains remain configuration beneath it. Sources: RFC 1034; ICANN TLD listings.
Related keywords
- second-level domain
- SLD
- root domain
- apex domain
- registrable name