MySQL (officially pronounced as /maɪ ˌɛskjuːˈɛl/ "My S-Q-L", and unofficially as /maɪ ˈsiːkwəl/ "My Sequel") is an open-source relational database management system (RDBMS); in July 2013, it was the world's second most widely used RDBMS, and the most widely used open-source client–server RDBMS. It is named after co-founder Michael Widenius's daughter, My. The SQL acronym stands for Structured Query Language.