A fragment in SEO refers to a section of content on a web page that is incomplete or isolated from the rest of the page's content. This fragment can be a sentence or a paragraph that has no context and cannot stand alone as a complete thought. Google's algorithms consider fragments as low-quality content, which can negatively impact a website's SEO ranking.

Fragments can occur due to a variety of reasons. One common cause is when a website pulls content from other sources without providing proper attribution or context. Additionally, when a website removes content from a page without updating the links or references that lead to that content, it can result in fragments.

To avoid fragments, it is essential to ensure that all content on a web page is complete and contextualized. If content is being pulled from other sources, it is crucial to attribute the original author and provide context for the content. It is also essential to make sure that all links and references on a web page lead to relevant and complete content.

In conclusion, fragments can damage a website's SEO ranking and should be avoided whenever possible. By ensuring that all content on a web page is complete and contextualized, website owners can improve their website's SEO ranking and provide a better user experience for their visitors.