(123) 456-7890. Everyone knows the first three digits are the area code, but most can't name the other sections. I learned the middle three as the "prefix," but I've heard some people call it an "exchange." The prefix for my house number is 567 and for years I wondered why they chose that. As a child I could tell it was by neighborhood — all my neighbors and local businesses used 567 — but I could never understand why I was 567 and the next neighborhood over wasn't 568.

It wasn't until the other day when I asked dad what his telephone number was growing up and he replied, "Oh, it was WALNUT-519." There was a long pause before I said, "Wait, what?" It turns out the letters were the "exchange," which was basically your local telephone center that connected all the lines. Dad described a large building in our neighborhood with wide windows, and you could see the machines chugging along as people called. An area the exchange covered would be given a name, and your personal line number would be slapped on the end. Dad's growing up was WALNUT, and he explained there were many famous ones known nationally, like around Madison Square Garden was PENNSYLVANIA for obvious reasons, MURRAY HILL was the east side, and Morningside was UNIVERSITY. Ours was LORRAINE, which on a number pad is 5677243, shortened to 567. An exchange became influential; mom told me her stationery used to have her business' word on it, and around our neighborhood lots of places where called Lorraine: Lorraine Florist, Lorraine Butcher, Lorraine Fabrics...

People became upset when the exchanges were dropped in the 60s for a purely numeric system because the exchanges were easier to remember, but I can understand why: It's probably easier to just generate a number instead of a word. Still, it would've been interesting to be known as a Lorraine instead of a 567.