A plugin system is a software architecture that allows additional features or functionalities to be added to an existing application without altering its core structure. This is achieved by using small, modular components called plugins. Each plugin can be developed independently and integrated into the main application, enabling users to customize their experience based on their specific needs. Plugins can be found in various software applications, including web browsers like Google Chrome and content management systems like WordPress. This flexibility allows developers to extend the capabilities of their software easily, fostering a diverse ecosystem of tools and enhancements that can improve user experience and functionality.