---
id: "third-level-domain"
kind: "glossary-term"
title: "三级域名"
language: "zh-Hans"
category: "TLD类型与计划"
updated: "2026-10-10T12:00:00Z"
canonical: "https://tldlog.com/zh/cihui/sanji-yuming/"
translations:
  en: "https://tldlog.com/glossary/third-level-domain/"
  es: "https://tldlog.com/es/glosario/dominio-tercer-nivel/"
  de: "https://tldlog.com/de/glossar/third-level-domain/"
  fr: "https://tldlog.com/fr/glossaire/domaine-troisieme-niveau/"
  it: "https://tldlog.com/it/glossario/dominio-terzo-livello/"
  pt-BR: "https://tldlog.com/pt/glossario/dominio-terceiro-nivel/"
  ru: "https://tldlog.com/ru/glossariy/domen-tretego-urovnya/"
---

# 三级域名

域名中从顶级域向左数第二个部分。在example.co.uk中，三级部分是“example”。在某些国家和地区代码顶级域下，公众注册的正是这一级。在其他域名中，它只是所有者自行创建的子域名，例如shop.example.com。

## 相关术语

- [二级域](https://tldlog.com/zh/cihui/erjiyu/)
- [子域名](https://tldlog.com/zh/cihui/ziyuming/)
- [ccSLD](https://tldlog.com/zh/cihui/ccsld/)
- [ccTLD](https://tldlog.com/zh/cihui/cctld/)
- [TLD](https://tldlog.com/zh/cihui/tld/)