---
type: Glossary Term
title: "Canonical tag"
description: "An HTML hint that tells search engines the preferred URL for a piece of content."
resource: "https://prerendering.com/glossary/canonical-tag"
tags: [indexation, glossary]
timestamp: 2026-05-11T00:00:00Z
---

# Canonical tag

An HTML hint that tells search engines the preferred URL for a piece of content.

A <link rel="canonical" href="..."> tag in the document head signals which URL Google should treat as the source of truth for duplicate or near-duplicate pages. Misuse — pointing all canonicals to the homepage, drifting between client and server renders, or chaining canonicals — causes indexation loss.

## Related

- [Canonical Issues on JavaScript Websites](/blog/canonical-issues-on-javascript-websites.md)