The Zone Improvement Plan (ZIP) Code system is a numbered coding system which facilitates efficient mail processing. The most complete ZIP Code is a 9-digit number consisting of five digits, a hyphen, and four digits which the USPS describes as its trademark ZIP4. The first 5 digits, found in the zip field, represents the first 5-digit ZIP Code.
See also:
postal_code- Place Data Dictionaryzip_four- Place Data Dictionaryworkplace.postal_code- B2C Link Data Dictionaryworkplace.zip_four- B2C Link Data Dictionary