Software Development Lifecycle.
SDLC is a process followed for a software project, within a software organization. It consists of a detailed plan describing how to develop, maintain, replace and alter or enhance specific software. The life cycle defines a methodology for improving the quality of software and the overall development process.
To learn more, the best place to start is https://https://www.geeksforgeeks.org/software-development-life-cycle-sdlc/