At various times, in various places, Jews were not allowed to have last names. When times changed and they were allowed to, they often took the names of their occupations, or physical or character traits, or the town or province they were born in or lived in. Other names have a more historical foundation, such as names reflecting cohen, israelite and levite ancestry. If you trace the origin of your family name, please consider sharing it here.

Chavkin
     In Belorussia, it was common to adapt a woman family member's name as the family name. Hence "Chava" became Chavkin, "Dvora" became Dvorkin, "Rivka" became Rivkin, etc. Chavkin apparently originated in 1790 when a Belorussian Jew named Abraham married a woman named Chava. According to A Dictionary of Surnames from the Kingdom of Poland, the name CHAWANSKI was found in the Suwalki area and stems from the name Chawa (khave in Yiddish; also Chowanski, Chawowicz, Kawin, Kawicz). The original Hebrew name is hawoh or Chavah , which is generally translated to Eve or Eva. The name CHAWKIN is found in Lodz. CHAVKIN, KHAFKINE, HAVKIN, HAFFKINE, CHAWKIN are all variables of the same name. (Source: Darla Chavkin Stone.)

Kaplan
     This Jewish family name derives from the Latin word cappella a small Christian prayerhouse, which in turn produced the term chaplain, the person who conducts the prayers. Jews took the name Kaplan, particularly in Eastern Europe, as a vernacular equivalent of the name Cohen.
    The first high priest (cohen) of the Jews was Aharon, elder brother of Moses, who led the children of Israel out from slavery in Egypt to the promised land. It was his descendants who performed the consecrated duties of the cohanim in the tabernacle and the temple in Jerusalem until the destruction of the second temple by the Romans in 70 c.e.
     The surname Cohen, or ha-Cohen (the priest), is as ancient as the function itself and throughout the diaspora it is one of the most widespread sources of Jewish family names (although not all Jews bearing a name linked to cohen are actually of priestly lineage).
     One of the earliest records of Kaplan as a family name is that of Abraham Kaplan in 1698. Distinguished bearers of the name include the polish preacher and philanthropist, Nachum ben Usiel Kaplan (1811-1879), the Latvian-born Hebrew poet Seeb Wolf Kaplan (1826-1887) and the Russian-born zionist workers' leader Eliezer Kaplan (1891-1952), the first minister of finance of the state of Israel. (Source: Nahum Goldmann Museum of the Jewish Diaspora)

Okun/Oklin
     When Russia ordered all Jews to assume surname in the 1640's, Freda Horvitz's Zayde was a fisherman whose nickname was the commodity he sold, a perch called okun in Russian. Okun became Oklin due to the carelessness of a U.S. immigration clerk. (Source: Recollections of Harry Katz.)

Sverdlov
See the exploration of the history and variations of this name at Andrew I. Sverdlove's Sverdlov site.