what is alpha in stock market?

 In the stock market, "alpha" is a measure of the performance of an investment relative to a benchmark index. Positive alpha indicates that the investment has performed better than the benchmark, while negative alpha indicates underperformance. Alpha is often used as a measure of a portfolio manager's skill, with a high alpha indicating that the manager has been able to generate returns that are not explained by the overall market. It is a measure of risk-adjusted return.