The term “Jew” is used in the Book of Mormon with two possible meanings: (1) a descendant of Judah, the son of Jacob (or, perhaps in a more general vein, a member of the house of Israel), and (2) a citizen of the kingdom of Judah of this particular period.
Lehi and his descendants are definitely not descendants of Judah (see 1 Nephi 5:14), but they might be considered Jews in the sense that they were citizens of the kingdom of Judah. Thus Nephi states, “I have charity for the Jew—I say Jew, because I mean them from whence I came” (2 Nephi 33:8). Also, the Lord refers to the Lamanites of our day as “a remnant” of the Jews. (D&C 19:27.)