Jude is a translation of the Greek Joudas, which again is a translation of the Hebrew Judah. In English Bibles, the Greek is normally translated as either Judah or Judas. Traditionally Jude is used for this final letter of the New Testament in order to distinguish him from Judas Iscariot, the one who betrayed Jesus Christ.1
1 Jude, a servant of Jesus Christ and brother of James, To those who are called, beloved in God the Father and kept for Jesus Christ: