In school you read the topic about what is meant by interest. The real answer of what is meant by interest is that interest rate is approximately the nominal interest rate minus the inflation rate. Regarding what is meant by interest the first includes the possibility that the borrower will default or be unable to pay on the originally agreed upon terms, or that collateral backing the loan will prove to be less valuable than estimated. According answer of what is meant by interest the second includes taxation and changes in the law which would prevent the lender from collecting on a loan or having to pay more in taxes on the amount repaid than originally estimated.
What is meant by interest relates the third which takes into account that the money repaid may not have as much buying power from the perspective of the lender as the money originally lent that is inflation, and may include fluctuations in the value of the currencies involved. If you want to know nominal interest the answer of what is meant by interest rates include all three risk factors, plus the time value of the money itself. Regarding what is meant by interest the inflation rate will not be known in advance. The complexity increases answering what is meant by interest for bonds issued for a long term, where the average inflation rate over the term of the loan may be subject to a great deal of uncertainty. With these references you can now answer what is meant by interest.
