A search engine is a software program that allows users to search for content on the World Wide Web. Users are able to enter keywords and phrases to search for a particular query. The search engine in turn, returns a list of content available on the Web that matches the search query.
The list of content returned to the user is known as a Search Engine Results Page (SERP). Search engines use complex algorithms to determine the ranking order of results, using keyword density, page load speed and links to determine the most relevant results.
A few of the search engines in use today include Google, Bing and Yahoo with Google being by far the most popular.
