What Does Forex Mean Anyway?

I see a lot of ads for Forex trading here and there, but I’ve never really known what it is. It’s clearly a hot topic on the web, and many blogs seem to be discussing various tips and techniques. But I still didn’t know what the hell ‘Forex’ meant.
Then I got an email from Investopedia titled: “Forex Training“.
Hmmm… I thought, this might give me a clue. But then again, maybe not. When I followed the link, this is what I got:

“What Does Forex Training Mean?
A form of instruction or mentorship that provides information on forex trading tactics, methods and successful practices. Forex training acts as a guide for the retail forex trader, providing insight into successful strategies, signals and systems as well as other general information on Forex trading.”

Wow! That seems more like a definition of training as it applies to Forex trading, but what is Forex Trading?
So, I did a little more digging, and eventually found this:

“What Does Forex – FX Mean?
The market in which currencies are traded. The forex market is the largest, most liquid market in the world with an average traded value that exceeds $1.9 trillion per day and includes all of the currencies in the world.”

It all makes sense to me now. It’s a bet on whether a given currency’s value will rise or fall. This is what George Soros made his billions in. I just don’t understand how it can be such a common term, and yet so narrow in its understanding. I guess if you don’t know what Forex means, you don’t need to know?