Someone asked me if the neck on my P bass was "C(1 3/4")-neck". I replied it was 1 5/8" with a C neck profile LOL. I didn't realize that he was probably referring to "C" as a synonym for 1 3/4". I've never seen this terminology before. It's certainly not used with guitars. Are there letter categorizations for different nut widths when referring to basses? Is it common? Just curious.