The term "built-in" refers to features or components that are integrated into a product or system from the start, rather than being added later. For example, a built-in microwave is designed to fit seamlessly into kitchen cabinetry, providing a clean and organized look. This integration often enhances functionality and saves space. In technology, "built-in" can describe software or hardware that comes pre-installed in a device. For instance, a smartphone may have built-in apps like a calendar or camera, allowing users to access essential functions without needing to download additional software.