The term "key question" refers to a crucial or essential inquiry that is central to understanding something. It is often used in research, where it may be considered as one of the main points of focus for investigation and analysis. In other contexts, such as problem-solving or decision making, it could refer to an important query that needs to be addressed before moving forward with a solution or choice. Overall, "key question" signifies a fundamental issue that requires attention in order to unlock deeper insights or make informed decisions.