A sitemap is a file on a website that contains a hierarchical list of all pages on the website. It serves as a guide for search engine crawlers that search the website to index the content.

The sitemap can be created in various formats, including XML and HTML, and usually contains information such as the URL of each page, its last update, its priority in relation to other pages on the website and a description of the content. Using a sitemap can help to ensure that all pages of the website are indexed by search engines and that no important pages are overlooked. If a website has multiple levels of pages or a complex structure, a sitemap can help search engine crawlers find and index all pages.

A sitemap can also help search engines better understand the topicality and relevance of a website's content. By indicating the last update date of each page, a sitemap can inform search engines which content is regularly updated and which may be out of date.