glossary?

I'm really really new to chess and I'm wondering if there is a glossary of terms - with simple, basic definitions - anywhere on this site?

I've been having lots of fun with the Tactics Trainer and Chess Mentor, but they often use terms I don’t fully understand, and I find myself digging all over the forums or on the internet somewhere trying to understand a concept, and then I forget where I was in the lesson...  Obviously, named strategies would be nice to have a definition for. But I’m looking more for terms that are normal words that we all know the meaning of, but as I get into the lesson I realize I don’t understand what it means in that context.

For example I’m on a lesson right now called “Balancing Imbalances.” Of course I know what “balance” and “imbalance” mean, but as I get into the lesson I realize I don’t know what I’m supposed to be looking for that is either balanced or imbalanced.  Is it number of pieces? Positions? Area of the board controlled? All of the above? None of the above?  Or “tactics.” I know that a “tactic” is a plan, a means to reach an end, but what’s the difference between “tactics” and “strategy”?  Are tactics short term, long term, both? Can you have a tactical plan for a whole game? Or is that a strategy?

I know these words can mean different things to different people in different situations, and I’m not looking for a precise definition, or to try to parse out specifics. But a glossary for beginners, with general definitions of basic terms and concepts for quick reference. Is there anything like that on this site?    

http://www.chess.com/chessopedia/