Kaplan is a fairly common name among Ashkenazi Jews. And until last week I had no idea what it meant, although I had noticed that it is particularly common among Kohanim, members of the priestly clan, who trace their lineage back to Aaron the High Priest, brother of Moses.

Meeting two (apparently unrelated) Kaplans side by side in the synagogue, and noting that both of them were indeed Kohanim, I realized that it was time to do a bit of research.

It turns out that the origin of Kaplan lies in the Latin word cappella (literally “cape”), which also gave us the English words chaplain and chapel. Since Kohen literally means “priest,” it makes sense for them to receive the rough Latin equivalent for their family name.

It thus joins Cohen, Katz, Kagan, Azulai and other names denoting that the bearer is of Kohen lineage.

It is important to note that many Kaplans, including most Chabad.org authors with that name, are not Kohanim. How did this come to be? A couple of possibilities:

  1. It may be that they were never Kohanim in the first place, perhaps having received that name because they were rabbinic leaders or otherwise viewed as “priestly.”
  2. They may have inherited the originally Kohen-related last name through the female line, while the priestly status is conferred exclusively through the male side.
  3. People often assumed false last names in order to avoid conscription into the Czarist army or to cross borders, and the new last names stuck even after they were no longer needed.
  4. Sometimes the name was adopted relatively recently and does not reflect any historical status of the family. A case in point would be Rabbi Aryeh Kaplan, whose Turkish born grandparents changed their name from Carmona in order to fit into a mostly Ashkenazic Jewish community in New York.

Note that if a Kaplan you know is a Kohen, it is a mitzvah to accord him with respect. This includes not asking him to fetch something or otherwise perform demeaning work for you. On the ritual side, he is honored with leading the Grace After Meals and receives the first Aliyah during Torah reading.

Some mitzvahs unique to male Kohanim, even nowadays, include conferring the Priestly Blessing (Birkat Kohanim), staying away from corpses (and cemeteries), and not marrying a convertess, a divorcee or others (read why here).