MySQL is an open-source relational database management system (RDBMS) widely used for managing and storing structured data. It uses SQL (Structured Query Language) for querying and manipulating data, and is known for its speed, reliability, and ease of use. MySQL is commonly used in web applications, content management systems (like WordPress), and for data-driven applications. It supports features like ACID compliance for transaction reliability, replication, and scalability. MySQL is often chosen for its strong community support, flexibility, and compatibility with various programming languages and platforms.