Yeah, it's just not cut-and-dried. Even the Webster definition of law isn't correct in any kind of reliable way, it is just an interesting distinction to draw. For example, we often talk about the "ideal gas law", even though it is well known its limitations and it does not conform to the above definition of a law. It is more like the "ideal gas model" or "ideal gas assumption", but we call it a law because it is a simple concise mathematical statement of a useful idealization. The same is true for Kepler's laws, for that matter-- there is actually "Newton's modification to Kepler's law", and even that isn't a law by the above definition, unless by "given conditions" they mean "the very ideallzation that defines the law". Which is pretty circular. Let's face it, words are fluid and contextual, and dictionaries do not save us from the fact that communication is challenging.