1. Billing term which indicates that the payment terms of the invoice are based on a date other than the date on which the invoice was created. For example, an invoice created on January 15th but marked 'as of January 5th' with credit terms of 30 days, would be due on February 5th.
2. Date on which an agreement, condition, order, or statue becomes effective or operative.
3. Date to which the given data or piece of information applies.