A design pattern in software engineering is a general repeatable solution to a commonly occurring problem within a given context in software design. It provides a template or blueprint for how to address issues in software architecture, fostering best practices while promoting code reusability and maintainability. Common examples include the Singleton pattern, which restricts the instantiation of a class to one object, and the Observer pattern, which facilitates communication between objects. By utilizing design patterns, developers can avoid reinventing the wheel, speeding up the development process and ensuring consistency across projects.