StackOverflow has questions about a topic. Meta-StackOverflow has questions about the questions in StackOverflow - for example, "is this question on topic?". X and Meta-X usually have similar relationships.
Logic is (roughly) about formal reasoning. Meta-logic is reasoning about logic, or why logic works.
Also, the relationship between physics and metaphysics and other similar pairs of words doesn't follow these "rules", and have independent definitions; you should look at their definitions and ignore the common root.
This is my admittedly informal understanding. I don't have a more formal understanding, but I don't have any practical problems with the concept either. Hope this helps!