Backdating or antedating is when a document is signed with a timestamp that has an earlier (older) date and/or time than when the document is actually signed.
Antedating can also refer to: Antedating (lexicography), finding attested use of a word or phrase earlier than the previous earliest known use Antedated contract, takes effect earlier than its signing date Antedated cheque, dated earlier than its date of signing
See also Forward dating, signing a document with a timestamp representing a later (more recent) point in time than the time the document was actually signed Chronological dating, attributing an event to a date in the past such that chronology is established