Cognizance: having knowledge of something. 

When you possess cognizance, you possess knowledge. 

As G. I. Joe says, “Cognizance is half the battle.”  Or, something like that.

Cognizance can also mean perception, awareness, the ability to notice things. 

Cognizance ultimately comes from the Latin word con (with) and the Greek word γιγνώσκω (gignosko) meaning, I know.  Naturally, the word took a while to show up in English.  First it travelled through French, where is was conoissance (knowledge, wisdom).