I don't think anyone reasonable actually suggest that one has to memorize the exact book definitions, but simply to be demonstrate that they understand the impo

I don't think anyone reasonable actually suggest that one has to memorize the exact book definitions, but simply to be demonstrate that they understand the important parts. Not being able to give any explanation or sign that you've at least heard of it is a completely different story from not being able to recall what the letter C stands for (consistency IIRC?). As the saying goes: If you think you understand something, and you can't explain it to someone else, that you probably don't really understand it.