cautio

Roman, Scots, & civil law

1. :  an oral or written agreement to indemnify :  guaranty: a :  a written assurance given as evidence of the receipt of money or as an acknowledgment of the making of a promise or of an existing state of affairs b :  an agreement by one furnishing security, a pledge, or a mortgage c :  an agreement often imposed by a judge or magistrate whereby one guarantees to protect another from loss or harm caused by the guarantor or a third person for whom the guarantor is responsible or whereby one guarantees payment or performance of an obligation of another