Glossary
What Is canonical (Canonical URL)
canonical is a link tag declaring a page's preferred address, used to consolidate duplicate content signals.
- Author
- Xingge
- Published
- 2026-11-09
- Updated
- 2026-11-09
- Level
- L2 Reproducible
- Version
- 1.0
Term details
- Name
- What Is canonical (Canonical URL)
- Type
- Glossary
- ID
- canonical-en
What Is canonical (Canonical URL)
canonical (Canonical URL) is a link tag that declares a page's preferred address, used to consolidate duplicate content signals. canonical cannot replace a 301 and must not be misused across unrelated topics.
Definition
This site's working definition: canonical is a declaration inside a page telling crawling and indexing which address is authoritative for that content; it uses an absolute URL and must match an actually reachable address.
When the same content has multiple entry points, all entry points point to the same address; when an old address is revised, use a 301 first and then use canonical to consolidate.
Boundaries: what it is easily confused with
| Easily confused concept | Key difference |
|---|---|
| 301 redirect | A 301 changes the access address; canonical only declares |
| Sitemap | A sitemap lists indexable pages; canonical sets the preferred address |
| Short link | A short link is a redirect service, not a content consolidation tool |
Common misconceptions
- Using canonical instead of a 301. Users still land on the old address, and signals are not fully equivalent.
- Setting canonical between unrelated pages. Cross-topic consolidation is treated as an anomaly.
- Pointing canonical at an unreachable address. A declaration must be openable.
Basis and verification
This definition is this site's working definition, marked L2. This site's rule is that each page's canonical points to its own absolute address, and parameter pages mark their indexing policy separately.
Review cycle: 180 days.
Related sections: glossary index, method index, metric index, editorial policy.