overriding rule -- meaning?

Question

Example with a context (The Object-Oriented Thought Process by Matt Weisfeld, 3rd Edition):

There is no question that today’s software systems are quite complex.To build quality software, you must follow one overriding rule to be successful: Keep things as simple as possible. For large software systems to work properly and be easily maintained, they must be broken up into smaller, more manageable parts. How do you accomplish this? In a 1962 article titled “The Architecture of Complexity,” Nobel Prize winner Herbert Simon noted the following thoughts regarding stable systems...

1. How do you understand the phrase overriding rule and what does it mean to you? Obviously, an overriding rule is simply a kind of rule, but what kind of rule is it exactly? Something like a cardinal rule or a rule so important that it trumps everything else when applied?
2. Have you ever heard this expression used before?

Answer 1

An overriding rule is a rule "above" (meaning more important than) all others.

So you could write:

To build quality software, you must follow one rule that is the most important, in order to be successful

or

To build quality software, you must follow one rule that is more important than any others, in order to be successful

in order is optional but sounds better to me that way.