What is the best definition of "Internal Rate of Return (IRR)"?

IRR can be defined as the discount rate at which the present value of all future cash flows (or monetized expected hypothetical benefits) is equal to the initial investment, that is, the rate at which an investment breaks even. It can be used to measure and compare the profitability of investments. If IRR is taken as the key criterion, the project with a higher IRR value should be chosen.