Loading speed, web and servers
canonical
In short and in plain language
Canonical is a hint in the head of a page.
It tells search engines which address is the right one. This helps when the same content sits under several addresses.
Search engines see the hint as advice. They do not have to follow it.
Definition
Canonical is a link in the page head that tells search engines the preferred address for the same or similar content. It helps when a page can be reached under several addresses, for example with parameters for sorting or filters. Search engines treat it as a hint rather than a fixed instruction.