Knuckle-Buster

Strict catholic school teachers (at least in the memoirs of Irish novelists). The opponents of John L. Sullivan. And, in another old fashioned reference, the machines people used to run credit cards back before ubiquitous computers and Wifi.

Nowadays, you swipe or insert your card and digital communication flitters around the ether for a few seconds. Someday in the near future, we’ll just think “charge it” and our brain implants will alert GoogAmaSoft of our purchase, and the product will immediately appear in our habipod, delivered by teleporting drone.

But, circa 1982, you gave your card to the merchant and they took out this clunky metal device that looked like a broken shoe-sizer. They put the card into the machine along with a few carbon slips. Then, with much effort, they pushed a heavy square slider back and forth over the card (potentially hurting their knuckles...hence the nickname).

This process made an impression of the card on the slips of paper. These would then get sent to the credit card issuer for payment.