A Database is an organized collection of data, generally stored and accessed electronically from a computer system. Databases are used to store, manage, and retrieve large amounts of structured information efficiently. They are essential components of web applications, enabling persistent data storage for user accounts, content, transactions, and other critical information. Databases can be relational (SQL) or non-relational (NoSQL), with popular systems including MySQL, PostgreSQL, MongoDB, and Redis. Database management systems (DBMS) provide tools and functionalities for data manipulation, querying, and administration, ensuring data integrity, security, and performance.