It refers to a system whose function is to systematically search the World Wide Web for specific information. The information search engines look for is specified in a textual webs search query. After finding the search results, the search engine usually presents a line of results. This line of results is known as Search Engine Results Pages (SERP).
The search engine results are either a mixture of links to different web pages, videos, images, articles, infographics, research papers, and other file forms. Some search engines also mine data present in open directories or databases. Search engines maintain real-time information with the help of an algorithm or web crawler, which they run. Hence, they can gather information from multiple sources and update such information whenever something new happens. However, there is some information web search engines cannot look for. This unsearchable information is called the deep web.
