A long straddle is an option strategy that involves buying both a long call and a long put on the same underlying asset with the same expiration date and strike price.
Natural hedging is a strategy aimed at reducing risk by investing in assets whose performance is negatively correlated through some internal or natural mechanism.
The option-adjusted spread (OAS) measures the difference in yield between a bond with an embedded option, such as an MBS or callable, and the yield on a Treasury bond.