What is the difference between the nominal interest rate on a loan and the real interest rate?

1. What is the difference between the nominal interest rate on a loan and the real interest rate?
2. What is the difference between the actual real interest rate and the expected real interest rate?
3. What is deflation? If borrowers and lenders expect deflation, will the nominal interest rate be higher or lower than the expected real interest rate? Briefly explain.
4. What are TIPS?