Here’s one more postal term to file away: Postnet. The Postnet is a ZIP code translated into a barcode and printed on a piece of mail. The Postnet makes it more efficient for automated machines to sort mail. Now that you have command of the ZIP code, try the challenge of understanding how to read a barcode.
http://blog.dictionary.com/zip-code/
The basic ZIP code has five digits. The first three digits refer to a sectional center facility (or SCF), what is basically a network of super post offices. All of the post offices that have those three digits in their ZIP code have their mail sorted and processed by the same SCF. The last two numbers designate the specific post office within an SCF’s territory. In the 1980s a new system was introduced called ZIP+4.
http://blog.dictionary.com/zip-code/
Answer:Five or Nine. Some zip codes have only five numbers, but, there are a few that have nine numbers because the area is so big and has so many addresses in it. A five digi…t zip code will look like this: 12345. A nine digit zip code will look like this: 12345-6789.
http://www.answers.com/Q/What_does_zip_number_mean
This refers to the first three digits of a 5-Digit ZIP Code. The first digit (0-9) designates the general area of the country with numbers starting lower in the east and increasing as you move west. For example 0 covers Maine while 9 refers to California.
http://zipboundary.com/zipcode_faqs.html
Rating Newest Oldest. Best Answer: Those last four digits are like a ZIP code within a Zip code. In 1983 the U.S. Postal Service began using the expanded ZIP (Zone Improvement Plan) code in order to expedite shipping to specific office blocks, mailing centers, and other areas that receive a high volume of mail. The last four numbers aren't mandatory, but they can help expedite delivery.
https://answers.yahoo.com/question/index?qid=20061215135637AAdPaZ4
“ZIP” is actually an acronym for Zone Improvement Plan. However, the USPS intentionally chose the acronym to indicate that mail travels more quickly when senders mark the postal code on their packages and envelopes. The general system of ZIP codes used today was implemented in 1963.
http://blog.dictionary.com/zip-code/
Those four numbers are for a specific address (Building, house, apartment) within the 5-digit ZIP code. If they are there, they are a way to help the mailman deliver them to the right place, in case the other part of the address is unreadable or missing. ny2la_usamex · 10 years ago.
https://answers.yahoo.com/question/index?qid=20061215135637AAdPaZ4
There are 5 digits in the ZIP code, plus a ZIP + 4 + 2 which adds  up to 11 digits.    To clarify: every street address has a USPS designated ZIP+4 code  and aids t…he USPS in efficient mail sorting and delivery.    The eleven-digit number mentioned above is only used for barcodes  on bulk mail.
http://www.answers.com/Q/What_does_zip_number_mean
This refers to the 5-digit ZIP code plus a 4-digit add-on number which identifies a geographic segment within the 5-digit delivery area, such as a city block, office building, individual high-volume receiver of mail, or any other distinct mail unit. The purpose of +4 codes is to aid efficient mail sorting and delivery.
http://zipboundary.com/zipcode_faqs.html
It is an extended zip code. In 1983, the U.S. Postal Service began using an expanded ZIP-code system called ZIP+4, often called plus-four codes or add-on codes.. This means that that every single mailable point in the country has its own 11-digit number (at least in theory).
https://answers.yahoo.com/question/index?qid=20061215135637AAdPaZ4
what does the numbers after the zip code mean
The numbers after the zip code means to aid efficient mail sorting and delivery.