"Capital gains tax. Here's a definition for you.
Well, capital means money and gains profit. Capital gains tax is a tax you pay when you make a profit on your money.
So let's say you make a 10K investment and ten years later you sell it for 25K. Wow!
You've just made a nice 15K profit. And you go buy yourself a new car with that. But just as you're driving it out, you get stopped by the tax person. Slow down there. They're after their share of that 15K profit you just made. That's capital gains tax".