In these cases, I don't believe the key question is, "To ask, or not to ask?" Instead, the main issue is, "How should I ask?"
If I was going to ask about rain check, for example, I wouldn't simply ask:
What is the meaning of rain check? Where did it come from?
That's basically asking everyone else in the community to do research for you. It exhibits laziness. A site peppered with questions like that will get old in a hurry.
Instead, I would try to find the answer myself. If I wasn't satisfied with the answers I found (perhaps they contradict each other, or maybe they don't come from authoritative, reliable sources), then I might ask the question here. That said, I'd be sure to include what I already found (with quotes and links), and also explicitly explain why I wasn't satisfied with the answers I had already uncovered.
By “doing your homework” first, and also sharing your findings, you'll have a much more robust question – one that is more likely to be appreciated instead of resented.