What does ZIP in ZIP code stand for?

Question

Answer 1

ZIP stands for Zone Improvement Plan.

What is ZIP code?
ZIP codes are a system of postal codes used by the United States Postal Service (USPS) since 1963. The term ZIP, an acronym for Zone Improvement Plan, was chosen to suggest that the mail travels more efficiently, and therefore more quickly (zipping along), when senders use the code in the postal address. Later similar coding system was adopted by many countries.

Answer 2

ZIP codes are a system of postal codes used by the United States Postal Service (USPS) since 1963. The term ZIP, an acronym for Zone Improvement Plan, was chosen to suggest that the mail travels more efficiently, and therefore more quickly (zipping along), when senders use the code in the postal address. Later similar coding system was adopted by many countries.
ZIP STANDS FOR ZONE IMPROVEMENT PLAN...