This is an interesting article from Cast Iron Collector website on an explanation of the meanings of the letters and number on the bottom of cast iron pans.
I never knew what they meant but was always curious. I did know that it was not the diameter of the skillet but after reading this article I am delighted with this bit of neat trivia.
For everyone that wishes Griswold was still making iron skillets, and I am one of those folks because Griswold iron skillets are the best ever made. However I did just run across the web site of Smithey Ironware and it looks like they may be making iron skillets as good as Griswold. They are expensive but as the saying goes “You get what you pay for” I am lucky enough to own a couple of Griswold’s that I love or I would be saving up to by these. Iron skillets become a family heirloom. They last forever and I just love mine.