Great question. To me a system is domain specific if it can’t be switched to a different domain without re-designing it. I can’t take Deep Blue and use it to sort mail instead. I can’t take Watson and use it to drive cars. An AGI (for which I have no examples) would be capable of switching domains. If we take humans as an example of general intelligence, you can take an average person and make them work as a cook, driver, babysitter, etc, without any need for re-designing them. You might need to spend some time teaching that person a new skill, but they can learn efficiently and perhaps just by looking at how it should be done. I can’t do this with domain expert AI. Deep Blue will not learn to sort mail regardless of how many times I demonstrate that process.