A kinnui (כנוי) or kinui (translated as "nickname") is the secular name held by Jewish people in relation to the language spoken by the country they reside in, differing from their Biblical Hebrew name.
The religious name is in Hebrew (for example, Moses ben Maimon; Joseph ben Gershon; Shlomeh Arieh ben David HaLevi;Gershom ben Judah; Devorah bat Avraham), and the secular name is in whatever language is in use in the geographic locality (for example, Isaiah Berlin; Solomon Lyon Barnard;Sigmund Freud;Golda Meir;Etta Cone ).
When Jews arrived in a new country, a secular name was often chosen from the local language. In Central and Eastern Europe, Yiddish was the secular language, so a Hebrew name was used in religious and Jewish community contexts and a Yiddish name was used (the kinnui) in secular contexts. In France, the secular name was in French; in Spain in Spanish, in North Africa and the middle East in Arabic, in ancient Babylon, the kinnui was in Babylonian and so on. Some kinnuim (the Hebrew plural of "Kinnui")are based on synonyms (words that have the same or similar meaning but are spelled differently); for example, Mikhail = Yekhiel; Menahem = Mendel; Asher = Anshel. Some Kinnuim represent the ancestral tribes of Israel, referencing the animal-like attributes of four of the sons of Jacob and one of his grandsons: Judah, the lion (e.g. the family name Lyon, Loewe); Benjamin, the wolf (e.g. the family name Woolf); Naftali, the deer (e.g. the family names Hirsch,Hersch, Harris); and Issachar, the ass (or the bear) (e.g. the family names Bar, Baer, Barell, Barnard, Bernhardt, Berthold, Schulter ); plus Ephraim, the fish (e.g. the family name Fish).