This page is about the Bid/Ask spread. For spread options positions, see the article on Options - Spread
Spread refers to the difference between two positions or prices. Generally, spread refers to the difference between the ask and the bid price of a security.
However, spread can also be used to refer to other comparable differences. A credit spread refers to difference in yield between two bonds of different quality or maturity. An options spread refers to the difference between the strike price of the option, and the market price of the underlying security.