A database is a collection of data that is organized in a logical and structured manner, designed to be easily accessed, managed, and updated. It can be software-based or hardware-based and used to store, manage and retrieve information. Databases can be very simple or very complex, and they are used in a wide variety of applications, such as storing customer information in a business, tracking inventory levels in a warehouse, or storing medical records in a hospital. There are many types of databases, such as relational databases, object-oriented databases, NoSQL databases, and graph databases, among others.