Plugin architecture is a design approach that allows software applications to be extended with additional features or functionalities without altering the core system. This is achieved by using plugins, which are separate modules that can be added or removed as needed. This flexibility enables developers to customize applications easily and allows users to enhance their experience by integrating new tools. In a plugin architecture, the main application provides a framework or interface that plugins must adhere to, ensuring compatibility. Popular examples of software that utilize this architecture include web browsers like Google Chrome and content management systems like WordPress, where users can install various plugins to tailor their experience.