(French) form of Christina. It was popular in the medieval period, when it appears to have been used interchangeably with Christian, and again in Britain at the end of the 19th century. In the United States it was particularly popular from the 1950s to the 1970s.
Irish: reduced Anglicized form of Gaelic Ó Fathaidh or Ó Fathaigh ‘descendant of Fathadh’, a personal name derived from fothadh ‘base’, ‘foundation’. This name is sometimes Anglicized as Green(e) as a result of erroneous association with faithche ‘lawn’.