The same page typically lives at many addresses: with and without www, with tracking parameters, with a trailing slash, in HTTP and HTTPS. Without a canonical each variant competes with itself for ranking; the tag says 'credit everything to this one'.
It is a hint, not a redirect — the URLs still work, the signals consolidate. On a multilingual site it pairs with hreflang: the canonical picks the true URL per language, hreflang picks the language per user. Pointing the canonical at a different page than the one served is the classic way to quietly deindex yourself.
Related terms
hreflang
Annotations that tell search engines which language and region each version of a page targets — so the Hungarian searcher gets the Hungarian page.
301 redirect
A permanent 'it moved' answer — sends visitors and nearly all ranking credit from the old URL to the new one.
SEO
Search engine optimization — making pages findable, indexable and worth ranking: technical health plus content people actually want.
The bench this belongs to
Web performanceA rebuild that loads on a phone on mobile data, in the country your customers are actually in. Core Web Vitals are the measurement, revenue is the point.
