verb (used with object), back·dat·ed, back·dat·ing.
- to date earlier than the actual date; predate; antedate: Backdate the letter so he’ll think I wrote it last week.
- (tr) to make effective from an earlier datethe pay rise was backdated to August
also back-date, by 1881 (implied in back-dated), from back (adv.) + date (v.1). Cf. antedate. Related: Backdated; backdating.