Rate of Return is either the “rate paid” on the unpaid balance of borrowed money, or the “rate earned” on the unrecovered balance of an investment, so that the final payment or receipt brings the balance to exactly zero with interest considered.
ROR is either the interest rate paid on the unpaid balance of a loan, or the interest rate earned on the unrecovered investment balance of an investment such that the final payment or receipt brings the terminal value to exactly equal “0”