If it is something that I do not know the definition or complexity of it I search it at that point. Sometimes this initiates the Wikipedia effect which can distract.
Naturally if this happens a lot during one reading that gives me a signal that perhaps I should take a step back and read more basic stuff.
I know this feeling. I do force myself to proceed but it feels like I'm cheating myself. Do you always hang around at that point until you clear up the question? What if it's something that would benefit if you allowed it to brew in the back of your mind? How do you keep track of such questions.
Sorry if i'm splitting hairs.