Effective Date

The date on which an insurance policy becomes effective.

The date as of which a reference is available as "prior art" in determining the patentability of an invention. The Effective Date of a reference usually something different from the Effective Filing Date of a patent application. MPEP 2126, MPEP 2126.01, MPEP 2128, MPEP 2128.02

The date by which routing and rating changes within the PSTN must be complete for the assigned thousands-block or the assigned CO Code. Also, the date by which the thousands-block becomes an active block. (Also referred to as "the LERG Routing Guide effective date.")