Beta
 
Beta is a measure of the volatility, or systemic risk, of a security or a portfolio in comparison to the market as a whole (the benchmark).  In general, a beta less than 1 indicates that of the investment is less volatile than the market, while a beta more than 1 indicates that the investment is more volatile than the market. 

Beta measures the sensitivity of a strategy or portfolio to its benchmark.  The beta of the market (as represented by the stated benchmark) is 1.00.  Accordingly, a strategy with a beta of 1.10 is expected to have 10% more volatility than the market.