One definition may be that you can use the device to write and compile all the programs it uses (any part of the OS, including the kernel itself), so that you don't need anything else. Kind of like a self-hosting compiler.
Not that you'd want to, but if you decided to do it, the option would be readily available.
Then modern game consoles and s smartphones qualify as well, they definitely have the resources to compile everything & only artificial limitations introduced by the manufacturers prevent that - which is sad & limits their potential.
Not that you'd want to, but if you decided to do it, the option would be readily available.