Most Americans know their ZIP code by heart. They type it into online forms, scribble it on envelopes and memorize it as part of their address. But not everyone knows the original meaning of the term.

Nowadays, people don't send letters to one another when they want to catch up. You may get holiday or birthday cards from your parents, grandparents or other family members and friends, but for the ...

Everyone has memorized exactly two ZIP codes: 90210 and whatever their own ZIP code is. We can thank a certain TV show set in Beverly Hills for that. Aside from that, general knowledge of these ...