In my experience, a law is generally just something that can be written as an equation. Sometimes, they’re definitions (like Ohm’s Law, R = V/I) or theorems (like Gauss’ Law, for appropriate definition of “charge” and “electric field”), and are therefore true absolutely. Sometimes, they’re part of a model or theory, and can have various amounts of experimental support (the Laws of Thermodynamics have a great deal of support, indeed). But sometimes, they’re only approximately true, or only in very restricted circumstances, such as Bode’s Law for the distances of the planets from the Sun, or Cole’s Law, that chopped cabbage must always be mixed with mayonnaise. So you can’t really say that laws are at a higher or lower level than theories: They’re not really in the same heirarchy.