Hebrew term that means “Lights and Perfections.” An instrument prepared of God to assist man in obtaining revelation from the Lord and in translating languages. See Ex. 28:30; Lev. 8:8; Num. 27:21; Deut. 33:8; 1 Sam. 28:6; Ezra 2:63; Neh. 7:65; JS—H 1:35.
Using a Urim and Thummim is the special prerogative of a seer, and it would seem reasonable that such instruments were used from the time of Adam. However, the earliest mention is in connection with the brother of Jared (Ether 3:21–28). Abraham used a Urim and Thummim (Abr. 3:1–4), as did Aaron and the priests of Israel, and also the prophets among the Nephites (Omni 1:20–21; Mosiah 8:13–19; 21:26–28; 28:11–20; Ether 4:1–7). There is more than one Urim and Thummim, but we are informed that Joseph Smith had the one used by the brother of Jared (Ether 3:22–28; D&C 10:1; 17:1). (See Seer.) A partial description is given in JS—H 1:35. Joseph Smith used it in translating the Book of Mormon and in obtaining other revelations.
This earth in its celestial condition will be a Urim and Thummim, and many within that kingdom will have an additional Urim and Thummim (D&C 130:6–11).