surety

1. Person or firm (such as a bank, bonding company, insurance company) that agrees to be primarily liable for the conduct, obligation, or performance of another. Surety who pays the debt of a borrower-in-default, in general, automatically acquires an assignment of a creditor's legal right to recover the amount paid from the borrower.

2. Formal pledge lodged, or sum of money deposited, as a guaranty against a damage or loss, non-fulfillment of an obligation, or unfaithfulness (such as of an accused on bail). See also surety bond.

3. Requirement that a product or system will meet its operational specifications under the specified conditions.