'co-endorsed' originates from the prefix 'co-' meaning 'together' and the verb 'endorse' from Latin 'indorsare', meaning 'to write on the back'.

'indorsare' transformed into the Old French word 'endosser', and eventually became the modern English word 'endorse'.

Initially, it meant 'to write on the back of a document', but over time it evolved into its current meaning of 'to support or approve'.