A "crawler" is a type of software program used by search engines like Google to explore and index content on the internet. It systematically navigates web pages by following links, gathering information about the content, and storing it in a database. This process helps search engines provide relevant results when users perform searches. The data collected by crawlers is essential for building search engine indexes, which are used to quickly retrieve information. Crawlers also help identify new or updated content, ensuring that search results remain current and accurate. This technology plays a crucial role in how we access information online.