What do you mean by crawler?

A crawler, also known as a web spider or web robot, is an automated program that systematically browses the internet to index content from websites. Crawlers are primarily used by search engines to gather information about web pages, which helps improve search results. They follow links from one page to another, collecting data on page content, structure, and updates. This process is essential for ensuring that search engines provide relevant and up-to-date information to users.