volatility　

volatility　1.波动不定；2.股价波动；3.波动　

1.economics：rate of change in price over a given period.Expressed often as a percentage，it is computed as the annualized standard deviation of the percentage change in the daily price.2.securities trading：size and frequency of rapid changes in the price of a security.If the causes of volatility are peculiar to security，it is measured by alpha；if the causes are related to the securities market as a whole，it is measured by beta.3.a measure of risk based on the standard deviation of investment fund performance over 3years.Scale is 1-9，higher rating indicates higher risk.Also，the standard deviation of changes in the logarithm of an asset price，expressed as a yearly rate.Also，volatility is a variable that appears in option pricing formulas.In the option pricing formula，it denotes the volatility of the underlying asset return from now to the expiration of the option.