Apy stands for Annual Percentage Yield, which is a measure of the return on an investment over a period of time. Essentially, it is the rate of return on an investment expressed as a percentage of the principal amount invested. It is used to compare different investments and is typically used to measure the performance of investments such as savings accounts, certificates of deposit, and money market accounts. The apy is calculated by taking into account the interest rate, the frequency of compounding, and the length of the investment period. It is important to note that apy does not take into account any fees or other costs associated with the investment, so it is important to compare the apy with other factors such as fees and minimum deposit requirements when choosing an investment.