What is the M2 measurement?

Can you please explain what the M2 measurement is in the context of finance and economics? Is it a widely used metric, and what does it specifically represent? Are there any key factors that contribute to its value, and how does it differ from other monetary aggregates like M1 or M3? Understanding the M2 measurement can help investors and policymakers gain insights into the money supply and liquidity in the economy, so it's crucial to have a clear grasp of its significance and implications.