volatility (noun)

the property of changing readily from a solid or liquid to a vapor

volatility, unpredictability (noun)

the trait of being unpredictably irresolute

"the volatility of the market drove many investors away"

excitability, excitableness, volatility (noun)

being easily excited

volatility (Noun)

The state of being volatile

Volatility

In finance, volatility is a measure for variation of price of a financial instrument over time. Historic volatility is derived from time series of past market prices. An implied volatility is derived from the market price of a market traded derivative. The symbol σ is used for volatility, and corresponds to standard deviation, which should not be confused with the similarly named variance, which is instead the square, σ².