Spot rate

In currency markets, the actual market exchange rate for a transaction now with standard immediate delivery (usually two business days after trade date).
In interest rate markets, the rate at which a single future payment is discounted back to the present. That is, where observable, the n-year spot rate is the yield to maturity of a zero coupon bond with a maturity of n-years. For maturities at which zero coupon bonds are not available, the spot rates can be bootstrapped from coupon paying bonds at those maturities since the price of these bonds is the present value of all their cash flows with each cash flow discounted at the appropriate spot rate.