← DictionaryCanonical URL
also called canonical tag, rel canonical
The declared preferred version of a page when duplicates exist.
The version of the page you want indexed.
What It Is
Canonical URL sits on the Technology side of the work, in the Search Tech area. The canonical meaning is the declared preferred version of a page when duplicates exist.
It is a mechanism rather than an opinion: set up properly it behaves predictably, and set up badly it fails just as predictably. That is the version worth keeping, because it survives contact with a real project.
How It's Used
Canonical URL earns its keep in build decisions, tooling and the plumbing behind a working system. It is usually discussed together with URL and Cannibalisation. The practical test is whether it is configured, documented and actually working.
Why It Matters
The cost of being vague about Canonical URL shows up later, not today. When it is unclear, small technical debts compound into a rebuild. It is worth pinning down before anyone builds on top of it.
Think of plumbing. Nobody admires it, everybody notices when it leaks. The version of the page you want indexed.
Termshift™
How the meaning shifts depending on who is using it, and where.
Practitioners use Canonical URL as shorthand and expect no explanation — the declared preferred version of a page when duplicates exist.
Outside the industry, most people would just say: the version of the page you want indexed.
The Bottom Line
Treat Canonical URL as a decision, not a description. The version of the page you want indexed.