Design patterns refer to reusable solutions to common problems that occur during software design and development. They provide a structured approach to designing and organizing code, improving code readability, maintainability, and scalability. Design patterns encapsulate best practices and proven techniques that have been refined and documented over time. They serve as blueprints for designing software components and systems, offering solutions to recurring design challenges. Examples of popular design patterns include the Singleton pattern, Factory pattern, Observer pattern, and Strategy pattern. By applying design patterns, developers can enhance code modularity, reduce code duplication, and promote software extensibility. Design patterns are an essential tool in software engineering, enabling developers to build robust, flexible, and maintainable software systems.