APR (Annual Percentage Rate) is a metric used to measure investment returns and represents the annualized return of investment products. It is typically expressed as a percentage and represents the expected returns of the investment product within a year. The calculation of APR can vary across platforms but generally includes investment gains, rewards, and other incentives.

In DeFi, APR is one of the key metrics for investors to evaluate different projects and platforms. A higher APR implies higher investment returns but also comes with higher risks. Investors can use APR to compare different investment opportunities and make decisions based on their risk tolerance and investment goals.