Etymologically, the word originates from the Latin term, capellanus or cappellanus, an office given to persons appointed to watch over the sacred cloak (cappa or capella) of St Martin of Tours.
[1] Its derivations were then found in many other European languages, including Yiddish, German, English, French, Czech, Polish, Norwegian, Croatian, and Hungarian.
Modern variations on Kaplan include Caplan, Chaplain, Chapling, Caplen, Copland, Kapelan, and Kaplin.
Kaplan or Caplan is also a surname common among Ashkenazi Jews, usually indicating descent from the priestly lineage (the kohanim), similar to the etymological origin of the common Hebrew surname Cohen.
[6][7] Not all Jews bearing this name belong to the priestly caste; at one time in the Russian empire male Jews other than priests were required to join the Russian army for 25 years, and a number changed their surnames to Kaplan in the hope of gaining exemption from military service.