"Shell and core" is a construction term that refers to a building's basic structure and exterior, which includes the framework, walls, roof, and essential services like elevators and stairwells. This phase provides a weather-tight shell, allowing for the interior to be completed later according to the needs of the tenants or owners. In this approach, the interior spaces are left unfinished, giving flexibility for customization. Tenants can design their own layouts and finishes, making it ideal for commercial properties where different businesses may require unique configurations. This method is often used in urban developments and large office buildings.