Plugin development refers to the process of creating software components that add specific features or functionalities to an existing computer program. These components, known as plugins, allow users to customize and enhance their software experience without altering the core program. Common examples include WordPress plugins that extend website capabilities or browser extensions that improve user interaction. Developers typically use programming languages and frameworks compatible with the host application to build plugins. The development process involves designing, coding, testing, and deploying the plugin, ensuring it integrates smoothly with the main software while maintaining performance and security standards.