Canonical tag
A canonical tag tells search engines which URL is the preferred version of a page when the same or similar content is reachable at multiple addresses.
Duplicate or near-duplicate URLs — from query parameters, tracking codes, or alternate paths — can split ranking signals and waste crawl budget. A canonical tag in the page head names the version that should be indexed and consolidates signals to it.
It is a hint rather than a directive: search engines usually respect it but can choose a different canonical if other signals disagree. Consistent internal linking and clean URLs make the hint more likely to be honored.
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