I am just adding this because Chat GPT wanted to use "hierarichal" in the definition, but it is not entirely ture.

In a lot of cases prerequisites fit the definition of hierarichal relationships. E.g. You would need to know what a river is before you could understand Mississippi River, which is a instance hierarichal relationship.

This does not hold in all cases for prerequisite links. E.g. a motor would be a narrower (subordinate) term to a car in a whole-part hierarchal relationship. However, knowing what a car is would not necessarily provide relevant information to understand what a motor is.