Beta - Financial definition
Concise definition of the term beta
The beta of an asset or a portfolio of assets measures its volatility in comparison to that of the market - or a representative market indicator - as a whole.
Comprehensive definition of the term beta
Beta also is the measure of an asset's return compared to that of the market as a whole, as the volatility of an asset represents variations of its price, which in turn are a key element of its return.