An interface is a point of interaction between different systems, devices, or software components. It defines how these entities communicate and exchange information. For example, a user interface allows people to interact with a computer program, while an application programming interface (API) enables different software applications to work together. In technology, interfaces can be graphical, like buttons and menus on a screen, or programmatic, like the code that allows one software to request data from another. They are essential for ensuring compatibility and functionality, making it easier for users and developers to work with various systems and applications.