What is the definition of nonresident in terms of parts of the operating system?

In the context of an operating system, a "nonresident" refers to data or code that is not currently loaded into memory. Instead, it is stored on a secondary storage medium, such as a hard drive or SSD, and is accessed only when needed. Nonresident data helps manage memory efficiently by allowing the system to utilize available RAM for active processes while keeping less frequently used information offloaded. This approach is essential for optimizing resource allocation and system performance.