The words before the lessons.
— optional, but it makes the rest easier
Money has a life of its own
Long before you make any decision about what to invest in, your money is already moving. An determines what each dollar earns or costs every year, and is the silent leak that erodes its purchasing power. The two together decide whether you're getting wealthier in real terms or just on paper.
The third force — the one most people underestimate — is time: turns small amounts into surprisingly large ones, given enough years — your — to do its work. The number that summarizes how it all turned out is the .
What you can buy with it
Most of what people call "investing" is buying one of three things. A makes you a fractional owner of a real business — the you put in entitles you to a slice of its profits, sometimes paid out as a . A is the opposite: you're the lender, and the issuer pays you interest by contract.
An is a shortcut: a basket holding hundreds of stocks (or bonds) at once, often built to track an like the S&P 500. When that's its only job, it's called an . The mix of everything you actually hold is your .
Why every choice has a cost
There is no investment that earns more than cash without also being able to lose more than cash. The technical word for that movement is , and its worst-case version is the — how far an asset can fall from its peak before it recovers, if it does. is the broader question: not just how much it might swing, but how badly the worst case could play out.
Markets cycle in long stretches called . The cleanest tool for softening any of this is : holding many uncorrelated things at once. The most useful habit is : buying the same amount on a fixed schedule, regardless of what the market did this week. And one more thing to watch: — how easily you can turn what you hold into cash without losing value.
The silent subtractors
Two things quietly subtract from what you keep, regardless of what the market does. are charged annually by funds, brokers, and advisors; over decades, even a single percent compounds into a meaningful fraction of your final balance. take a slice of every gain, dividend, or interest payment — though tax-advantaged accounts can defer or reduce them.
Both deserve real attention precisely because they're invisible day-to-day. They only show up in the difference between the chart you saw and the balance you actually have.
That's the vocabulary. Now the lessons.
Each of these words gets a full lesson — with worked examples, interactive simulations, and the math behind the headline. Start at Lesson 01 and the rest of the words will make sense in context.