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Second-Level Domain (SLD)

The label directly left of the TLD — the "example" in example.com — the part you actually register.

NTNamefi TeamAuthorVZVictor ZhouEditorJune 22, 2026
  • 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.

Related keywords

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  • root domain
  • apex domain
  • registrable name
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Contributors

Namefi Team

Namefi Team • Namefi
Author

Namefi is a collective of engineers, designers, and operators who obsess over building tools that make managing your onchain domain names effortless.

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Victor Zhou

Founder & Standards Editor • Namefi
Editor

Victor Zhou is a technology founder and standards editor focused on digital identity and trust. He founded Namefi, edits Ethereum Improvement Proposals, and previously led smart-contract architecture work at Google Labs.

His work sits at the intersection of naming, ownership, and the systems people use to establish identity online. That perspective makes him especially interested in the way names move between personal meaning, public recognition, and digital infrastructure.

For Namefi, Victor edits and writes about domains as durable digital identity: how names become ownable onchain assets, how tokenization changes custody and trust, and what naming can learn from the systems people use to establish identity online.

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