"Third-party integration" in software development involves connecting a software application with external services or components provided by another organization. This integration facilitates the utilization of pre-existing APIs (Application Programming Interfaces) that allow for enhanced functionality, such as payment processing, analytics, and data sharing. By incorporating third-party elements, developers can accelerate the development process, reduce costs, and improve user experience without reinventing the wheel. However, it also necessitates careful management of security and compatibility to ensure seamless operation within the primary application.