Final answer:
A mount-point is a directory where a file system is mounted and made accessible in an operating system. It is used when attaching external devices like USB drives to allow for access to their contents within the system's file structure.
Step-by-step explanation:
A mount-point is a directory (which should exist), on which to mount the file system. Mount points are essential in operating systems, particularly Unix and Linux systems, where they serve as the location where a file system is made accessible. For example, when you plug in a USB drive, it needs to be mounted to a specifically defined directory so that the operating system can access its contents.
This is often done through commands in the terminal or automatically by the system when the device is detected. An example of this would be the '/media/usb' directory, which could serve as a mount point for a USB drive. It is crucial to have proper permissions for the mount-point directory to allow for the successful mounting of the file system.