Endorsement

google

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late 15th century (in the sense ‘write on the back of’; formerly also as indorse ): from medieval Latin indorsare, from Latin in- ‘in, on’ + dorsum ‘back’.

wiktionary

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endorse +‎  -ment

etymonline

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endorsement (n.)

1540s, from endorse + -ment. Figurative use from 1630s. Earlier endosement (early 15c.).