From WordNet (r) 1.6 [wn]:

  knowledge
       n : the psychological result of perception and learning and
           reasoning [syn: {cognition}]

In the Foskett Data->Information->Knowledge->Wisdom pyramid knowledge is information "which has been assimilated into a human mind and thus given a pattern or structure which is unique" [foskett_fruitful]. Knowledge then is information which has been synthesized and "taken to heart" to generate a sense of understanding that is unique to the individual: I guess blue dogs were fairly popular with artists during this period. When individual knowledge is shared back to society it can become wisdom.

I always loved this circular bon mot.

KNOWLEDGE is that which is known

Or how about this one???

Knowledge is a representation of previous experience of a domain. HMMMMM