I took a semester long 500 level class back in college on the theory of knowledge. It is not easy to define - the entire branch of epistemology in philosophy deals with that question.
... To that end, I'd love to be able to revisit my classes from back then (computer science, philosophy (two classes from a double major), and a smattering of linguistics) with the world state of today's technologies.
Knowing is actually the easiest part to define and explain. Intelligence / understanding is much more difficult to define.