MySQL ("My S-Q-L", also commonly known as "My Sequel") is a relational database management system (RDBMS) that runs as a server providing multi-user access to a number of databases.
Some open source software project examples: Joomla, WordPress, MyBB, phpBB, Drupal and other software built on the LAMP software stack. MySQL is also used in many high-profile, large-scale World Wide Web products, including Wikipedia, Google (though not for searches) and Facebook.