term:

Surety

surety n

pl: -ties
[Anglo-French seurté, literally, guarantee, security, from Old French, from Latin securitat- securitas, from securus secure]
1 : a formal engagement (as a pledge) given for the fulfillment of an undertaking
2 : one (as an accommodation party) who promises to answer for the debt or default of another NOTE: At common law a surety is distinguished from a guarantor by being immediately liable as opposed to becoming liable only upon default of the principal. Under the Uniform Commercial Code, however, a surety includes a guarantor, and the two terms are generally interchangeable.

Source: Merriam-Webster's Dictionary of Law ©1996. Merriam-Webster, Incorporated. Published under license with Merriam-Webster, Incorporated.