The software development lifecycle (SDLC) is a structured process used to design, develop, and maintain software applications. It typically consists of several phases, including requirements gathering, design, implementation, testing, and deployment. Each phase has specific tasks and deliverables, ensuring that the final product meets user needs and quality standards. After deployment, the SDLC also includes maintenance to address any issues or updates needed over time. This cyclical approach allows developers to refine and improve the software continuously, adapting to changing requirements and technologies while ensuring efficient project management and delivery.