Jewelry manufacturers and designers use maker’s marks or stamps that feature their logo, name, or initials. In some cases, these can look like abbreviations. You will find 1000s of unique maker’s marks in recent and previous use, but these are typically a few of the typical types that use acronyms: https://jewelrypronunciation74073.ltfblog.com/21531199/style-fashion-drawing-no-further-a-mystery