A sitemap is an XML file that provides search engines with a structured list of URLs on a website, along with metadata about each page such as when it was last modified, how often it changes, and its relative priority. Sitemaps help search engines discover pages that might not be found through normal crawling, especially on large or complex sites.
The sitemap protocol, originally developed by Google and now supported by all major search engines, uses a standardized XML format. Each URL entry can include optional tags for lastmod (last modification date), changefreq (expected change frequency), and priority (relative importance within the site). SEO technical books on Amazon explain the specification.
For URL shortening services with glossary pages, article sections, and multi-language support, sitemaps are critical for ensuring all content is discovered and indexed. Each language version of each page should be listed with appropriate hreflang annotations to help search engines understand the relationship between translations.
Best practices include keeping sitemaps under 50,000 URLs and 50MB, using sitemap index files for larger sites, submitting sitemaps through Google Search Console, and referencing the sitemap in robots.txt. Webmaster tools books on Amazon cover submission procedures.