You probably know your ZIP code by heart. But do you know what it stands for?
ZIP stands for ZONING IMPROVEMENT PLAN. It started in 1943 during WWII. Thousands of postal workers left to serve in the war. This left the postal system understaffed and overcomplicated.
It started with just two digits for city and state: New York City and New York State, but was later updated in 1963 to the current 5-number system.
The first digit now designates a broad area. It ranges from 0 for the Northeast to 9 for the West. The next 2 digits are the code of the central post office in the region. That last two designate smaller post offices or postal zones.
A hyphen and four-digit code were added to some ZIP codes. This was to better sort mail in certain sectors.
These two digits indicate delivery sectors which could be an office or apartment building. The last two stand for a delivery segment which could mean a specific floor or department of a building.