 So that's why interest rates and bond prices are inversely related. Number two on my list, what does duration mean? This is a common term that we use all the time in the investment world. Duration is sometimes confused with maturity. They're similar, but not exactly. Maturity of a bond is just when you get your principal back, right? So in the previous example, you bought a 5% bond for 10 years. 10 years later, you get your $10,000 back or whatever amount of principal you use to invest in the bond.