[1] : The Collaborative International Dictionary of English v.0.48

backdate \back"date\ v. t.
   1. to make effective from an earlier date; to make
      retroactive. the increase in tax was backdated to january.

   syn: back-date
        wordnet 1.5

   2. to affix a date earlier than the present date; --
      sometimes done for fraudulent purposes. opposite of
      postdate.

   syn: back-date; predate; antedate.
        pjc

   note: backdate is sometimes used incorrectly for postdate.
see also:
postdate 

[2] : WordNet (r) 2.0

backdate
     v : make effective from an earlier date; "the increase in tax
         was backdated to january"

Backdate >> B Words
Backdate, definition of term: Backdate
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