To date before the true time; give an earlier date to than the real one: thus, to antedate a deed or bond is to give to it a date anterior to the true time of its execution.
To be of older date than; precede in time.
To anticipate; realize or give effect to (something) in advance of its actual or proper time.
noun.
A prior date; a date antecedent to another, or to the true or actual date of a document or event.
noun.
Anticipation.