Beta measures how sensitive an asset’s return is to movements in the overall market.
Interpretation:
beta = 1: moves roughly with the marketbeta > 1: more sensitive than the market0 < beta < 1: less sensitive than the marketbeta < 0: tends to move opposite the market
Beta is a measure of systematic risk, not total risk. That is why it belongs in Risk and Return rather than standing alone as a complete risk measure.