Volatility

Volatility is how violently prices swing up and down. High volatility means a wilder ride — gut-punch drops followed by sharp recoveries. Here's the deal Wall Street won't simplify: those swings are the price of admission for stocks' long-run returns. No volatility, no premium.

Example: Stocks routinely drop 10% or more in a given year — the admission price for their roughly 10% long-run annual returns.