Like with any other language, I've found that frequent interaction with financial terms improves your literacy and helps you make better connections between ideas. For instance, a few years ago when Southwest Airlines seemed to have much lower prices than everyone else, I read that they had bought futures contracts back when oil prices were low. Right there you have a company that's 'naturally short' oil, who 'hedged' against rising prices by buying 'futures', etc. A couple of good sources for financial news are the APM Marketplace podcast and Felix Salmon's blog on Reuters, and you can look up terms on Wikipedia when needed.

Keep in mind that a bunch of the commonly recommended finance books are either a bit pop-finance (Liar's Poker) or somewhat outdated (Intelligent Investor), which is OK if your goal is to be entertained or well-versed, respectively. Most authors have a thesis, and if you were to only devote time to one book and it happened to be something like Fooled by Randomness, you'd find yourself with a very skewed view of things. That's why I'd suggest current news if you're only interested in financial terms as they relate to your job.

And finally, like with any other jargon, realize that while it's useful to know and can help formulate ideas, a lot of people overuse it. Not saying this article does it, but I've seen finance people go "short" undesirable menu items at a restaurant. Don't let the gratuitousness make you think these terms are more important than they are :)