'backdate' originates from English, a compound of the adverb 'back' + the noun 'date', formed to mean assigning a date earlier than the actual one.

'backdate' emerged as a compound in English (written as 'back-date' in some older texts) and by regular usage developed into the modern form 'backdate' and its derivatives like 'backdating'.

Initially, it meant 'to give a date that is earlier than the true date'; this core meaning has remained consistent, though legal and commercial connotations (e.g., in finance or compliance) have become more prominent over time.