Oh boy, I have a lot to catch up on here. I visited the Mormon Family Research Center in Oakland, where I met Jeremy Frankel, the president of the SF Bay Area Jewish Genealogical Society. More on that, and what I learned about ordering LDS records, in an upcoming post.
Also, I connected online with Dave Howard, who is the leading researching about the Jewish community in Rezekne. His FamRoots.org and HorwitzFam.org sites are a treasure trove of information. I will be posting highlights and links to the most relevant stuff in an upcoming post.
For now, I thought I would post this excerpt from Alexander Beider's Dictionary of Jewish Surnames From the Russian Empire. Howard has a few small parts of the work available to view on his Horwitz site. Here is a section dealing with the surname Katz.
Since it is hard to read, I will summarize. Katz originates from the name Kohen, which means priest in Hebrew, possibly the same as Goan. Kats or Katz is an acronym for Kohen Tsadek (Kohen of righteousness). The name was common throughout the Russian Empire. Of course, our great-grandmother was Bette Katz, the wife of Julius Wolgemuth of Koenigsberg.
By the way, Beider has another volume on Jewish surnames in Galicia, which are likely to contain informative entries for Ringel and Kaufler. The books are published by Avotainu and are very expensive. I will be looking for where I can find them in a library.