Answer:
   
   The word Jew is English and is only used by Jews who speak English. It
   is derived from the Hebrew word, yehudi meaning Judean, which comes
   from the name of the tribe of Yehudah (Judah). Before the Babylonian
   exile, the Northern Kingdom of Israel essentially disappeared and only
   the Southern Kingdom of Judah remained. As a result, the name of the
   Southern Kingdom began to be used to refer to all the descendants of
   Jacob (Israelites).
   
   Note: Arabs are also descended from Abraham, but they certainly do not
   call themselves Jews. Why? Because they were not part of the tribes of
   Israel. Rather, they claim lineage through Abraham's son Ishmael.