ELI5: Explain Like I'm 5

Interest rate risk

Interest rate risk is the risk that changes in interest rates might reduce the value of something you own. Interest rates are always changing, and when they go up, the value of something you own might go down. For example, if you bought a bond for $100, and the interest rate goes up, the bond might only be worth $90 now. If you had to sell it, you'd lose $10. That's interest rate risk.