Here are some common phrases that originated from letterpress terminology:
“Upper case” and “lower case”: Originally, when printers organized their individual pieces of lead type they put the “big” letters in the top, or upper set of cases, and the “little” letters below.
“Mind your p’s and q’s”: Setting lead type can be tricky since the letters are backwards; p’s and q”s often
get mixed up.
“Out of sorts”: The most commonly used letters are referred to as sorts. When setting a long piece of text, it’s not uncommon to find oneself out of sorts!
“Coin a phrase": After text has been set into a chase (metal frame) it is locked up using quiones (coins) and a key, thusly “coining the phrase”.