Canonical tag
Definition
An HTML tag that tells search engines and crawlers which version of a page, among near-duplicates, is the one to treat as authoritative.
Why it matters
When the same content exists at more than one URL, a missing or incorrect canonical tag can split authority between them, and in the worst case, cause citation or crawling systems to pick an inconsistent or outdated copy.
Example
A product listed under both a seasonal URL and a permanent one should canonicalize to the permanent one, so that is the version any crawler treats as definitive.
Related terms
Sources
AI crawler
An AI crawler is an automated program, run by an AI company, that fetches web pages to train models, build a search index or answer a user's request.
Optimization
Structured data
Structured data is markup, commonly schema.org in JSON-LD, that describes the meaning of a page's content in a form machines can read.
Keep learning
What is Canonical tag?
An HTML tag that tells search engines and crawlers which version of a page, among near-duplicates, is the one to treat as authoritative.
Why does canonical tag matter?
When the same content exists at more than one URL, a missing or incorrect canonical tag can split authority between them, and in the worst case, cause citation or crawling systems to pick an inconsistent or outdated copy.
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