The term "Mobile Operating System" refers to software that allows a mobile device, such as a smartphone or tablet, to function properly. It is responsible for managing and coordinating all the processes and functions on the device, including controlling apps, managing memory usage, handling network connections, and providing security features. Some popular Mobile Operating Systems include Android, iOS (iPhone), Windows Phone, and Blackberry OS. These systems provide a platform for developers to create applications that can be downloaded and used by users of these devices.