Canonical tag
Definition
A canonical tag tells search engines which URL is the preferred version of a page when duplicate or near-duplicate content exists at multiple addresses, consolidating ranking signals onto one URL.
Duplication arises constantly without anyone intending it — tracking parameters, filter combinations, pagination, HTTP and HTTPS variants, trailing slashes. Canonical tags consolidate these so authority accumulates on one URL rather than being split.
They are a hint rather than a directive, and they are frequently misapplied: canonicalising every page to the homepage, or canonicalising across genuinely different content, both cause pages to disappear from the index.
Definitions are free.So is the audit.
Thirty minutes on a call, then a written 5-page plan inside 72 hours showing where this actually applies in your funnel — and what it is worth fixing first.