Databases are organized collections of data that allow users to store, retrieve, and manage information efficiently. They are essential for various applications, from small personal projects to large enterprise systems. Databases can be structured in different ways, with relational databases being one of the most common types, where data is stored in tables and relationships between them are defined. In addition to relational databases, there are also NoSQL databases that cater to unstructured data and provide flexibility in data storage. Overall, databases play a crucial role in enabling data-driven decision-making and supporting the functionality of modern applications.