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ZIP + 4

American  
[zip pluhs fawr, fohr] / ˈzɪp ˌplʌs ˈfɔr, ˈfoʊr /

noun

  1. a zip code of nine digits, used to facilitate accurate and prompt delivery of mail.

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.