**Whenever I learn something new, I divide them into concept and theory. **
Concept
Concept is basically the understanding of the process, from the beginning to the outcome. A good example will be mathematics. Let's say we're finding the permutation of A, B and C. It will be 3! or 3x2x1. Why? We start off with 3 options, after picking any letter among A, B and C, we'll have 2 options left then 1 option.
Theory
Theory is where everything is connected. And connections are very important to get fimiliar with new things. In fact, everything in our world is like programing. We have object, properties/characteristic, functions/effects/affects. For example, ileum can be an object. Properties will be containing numerous of villi and long in length which provides large surface area. Functions will be allowing food substances to be absorbed faster into blood capillaries and lacteal. This is where the magic appears, everything is linked together! Every object has its own properties or characteristics, and these properties can peform certain functions, just like programming.
Not only allow you to memorise things systematically, but also provides directions of thoughts. When you're asked about relationships/definations of a certain object, try start thinking from its properties then its functions, you will soon notice different object's relationships!