For a mobile application, the OC is defined by the hardware and software environment in the device, the target user, and other constraints imposed by various other stakeholders, such as a carrier.
This concept differs from the operating system (OS) by the impact of these various other stakeholders.
The network, spectrum, and wireless protocol all change in this example.
Situations exist where one can program in a context, with less concern about what hardware it will actually run on.
This is common with software written for, that interacts more directly with, personal computer (PC) hardware, or mobile phones.