Yield
A measure of return on a fixed income investment. While there are several types of yield measurements, the simplest views a fixed income investment's yield as synonymous with its interest rate. Yield in this case is calculated by dividing t he annual amount of interest a fixed income investment provides and dividing by the face amount of the investment. For example, a bond with a face amount of $1000 which provides $60 of interest a year has a 6% yield.

Yield Curve
The graphic representation of how the yield for a particular type of fixed income investment (such as triple A rated corporate bonds) changes over a range of maturities. Time to maturity is plotted on the yield curves' x-axis while yield is plotted on the y-axis.

Yield Spread
The difference of the yield between various securities.