What is another word for zip plus fours?
Pronunciation: [zˈɪp plˈʌs fˈɔːz] (IPA) 
The term "zip plus fours" refers to the system developed by the United States Postal Service for postal codes consisting of a 5-digit zip code followed by a 4-digit add-on code. However, there are several synonyms for this term, including "postal code extensions," "zip extensions," "zip add-ons," "zip+4 codes," and "united states postal service zip codes." These terms are used interchangeably to describe the same system of codes used to further narrow down the location of a mail recipient. Essentially, these synonyms refer to the same system of codes which have made mail delivery more efficient and faster in the United States.
