A canonical tag, also known as "rel canonical," is an HTML tag that indicates to search engines that a master copy of a page exists and which version of a page should be considered the main version. It is a way of telling search engines that a specific URL represents the master copy of a page and prevents problems caused by identical or "duplicate" content appearing on multiple URLs. Practically speaking, the canonical tag tells search engines which version of a URL you want to appear in search results. Canonical tags are used in SEO to help search engines index the correct URL and avoid duplicate content.
Some key points about canonical tags include:
- Purpose: The primary purpose of the canonical tag is to tell search engines which page is the main, original version and which are just duplicates that look the same.
- Syntax: Canonical tags use simple and consistent syntax, and are placed within the <head> section of a web page.
- Benefits: Using canonical tags can help prevent SEO problems caused by duplicate content, such as missed unique content, diluted ranking ability, and search engines picking the wrong URL as the "original".
- Implementation: Canonical tags can be implemented by adding the tag to the head section of the duplicate pages, pointing to the URL of the original page.
In summary, a canonical tag is an HTML tag that helps search engines determine the main version of a page and avoid duplicate content issues in SEO.