Reserve requirements refer to the amount of money that banks and other depository institutions are required to hold in reserve, either in cash or in deposits at the central bank. This requirement is set by the central bank, such as the Federal Reserve in the United States, and serves as a tool for monetary policy. By adjusting the reserve requirement, the central bank can influence the amount of money that banks have available to lend out, which can affect interest rates and inflation. Higher reserve requirements mean that banks have less money to lend, which can lead to higher interest rates and slower economic growth. Lower reserve requirements mean that banks have more money to lend, which can lead to lower interest rates and faster economic growth.