Does my evidence have to be during the same time period? Also, does it have to be as specific as to writing a vocabulary term?
Your outside evidence should be in the time period of your essay, and it should support your thesis. It doesn’t have to be as specific as writing a vocab. term; it could be information that is not brought out in any of the documents but which you believe strengthens your argument.
Outside evidence from outside the timeframe can be used, though this is not recommended, because it needs to directly support your argument, and it would be much easier to use evidence from within the time frame of the prompt.