Spread

The difference between the yields or volatility on two financial assets (aside from the bid-offer). More specific :
(1) The difference between the bid and ask price of a currency.
2) The difference between the price of two related futures contracts.
For options, transactions involving two or more option series on the same underlying currency.
In fixed income markets the credit spread is the difference in yields between fixed-income instruments of different credit qualities.
In oil markets, the crack spread is the spread between the price of crude oil and the refined (cracked) distillates such as gasoil and naphtha.
(3) With credit default swaps, the coupon of a CDS contract expressed as a percentage of the notional amount. The spreads reflects the probability of default of a reference entity: the higher the spread, the higher the probability of default.