Русско-англо-русский юридический словарь

The term "suretyship" denotes a relationship among an obligee and two obligors, the principal and the surety, in which the obligee is entitled to only one performance, the principal has the primary duty to perform, and the surety has a secondary duty to perform if and only if the principal fails to perform. (Contract Law in the USA by Gregory Klass)

Those interested in bonds are advised to access the judgement of Sir William Blackburne (sitting as a judge of the high court) in the case of Vossloh Aktiengesellschaft and Alpha Trains (UK) Ltd [2010] EWHC 2443 (Ch). This case judgement is dated 5th October 2010. At para 21 it states:

‘A contract of suretyship is in essence a contact by which one person, the surety, agrees to answer for some existing or future liability of another, the principal (or principal debtor), to a third party, the creditor, and by which the surety’s liability is in addition to, and not in substitution for, the liability of the principal.’ (brianfarrington.co.uk)