Delivery point
In a postal system, a delivery point (sometimes DP) is a single mailbox or other place at which mail is delivered. It differs from a street address, in that each address may in fact have several delivery points, such as an apartment flat, office department, or other room. Such a building (mainly only residential) is often called a multiple-dwelling unit (MDU) by the USPS.
In the U.S., the delivery point is normally encoded in the POSTNET barcode, in addition to the ZIP+4, although it is not part of the ZIP code itself. Since each city block or section of a rural route has a different sub-ZIP (the +4 part), and address numbers generally increase by 100 per block, the DP is the last two digits of most addresses. It may also be the last two digits of a suite number, the floor number, or an arbitrary number assigned by the local delivery unit.
