From Wikipedia on 17-Feb-2013
URL: http://en.wikipedia.org/wiki/Knowledge
Knowledge is a familiarity with someone or something, which can include facts, information, descriptions, or skills acquired through experience or education. It can refer to the theoretical or practical understanding of a subject. It can be implicit (as with practical skill or expertise) or explicit (as with the theoretical understanding of a subject); it can be more or less formal or systematic In philosophy, the study of knowledge is called epistemology; the philosopher Plato famously defined knowledge as “justified true belief.”
Hierarchies of Knowledge
Several hierarchical organizations of knowledge are described in Wikipedia:
Encyclopedia Britannica’s Propædia
Diderot and d’Alembert’s Figurative System of Human Knowledge
The hierarchical index of this website is another example, though not nearly as comprehensive. It’s interesting that I also chose a hierarchy as a way to organize knowledge, even though I’d never seen any of the other hierarchies before.