The K slur is an ethnic slur for a Jewish person, and it is considered one of the worst anti-Jewish slurs. The earliest recorded use of the word dates back to the 1880s. There are several theories about the origin of the word, but the most widely accepted one is that it may be an alteration of the endings "-ki" or "-ky" common in the personal names of Jews in Eastern Europe who immigrated to the United States in the early 20th century. Another theory suggests that the word comes from the Yiddish word "kikel," which means "circle". According to this theory, Jewish immigrants who were illiterate or could not use Latin alphabet letters signed their entry forms with a circle instead of the customary "X," which signified Christianity. Ellis Island immigration inspectors began calling such people "kikels," and the term shortened as time passed. There is also a theory that Irish immigrants to the United States first used the slur, perhaps based on the Gaelic word "ciabhóg". However, this theory has some competition from other linguists who champion different theories. Regardless of its origin, the K slur is a derogatory term that should never be used.