debenture: [15] Debenture is simply an anglicization of Latin dēbentur, literally ‘they are due’, the third person plural present passive of the verb dēbēre ‘owe’. It supposedly arose from the practice of writing debentur on IOUs in the late Middle Ages. The English word originally signified such IOUs issued by the government or the Crown – certificates of indebtedness, to give them their formal designation – and it was not until the mid-19th century that the modern meaning, ‘unsecured bond backed by the general credit of a company’, came into use. => debt, due, duty[debenture etymology, debenture origin, 英语词源]