Easton's Bible Dictionary (1897)
“doctrina;” LXX. “revelation”). See THUMMIM.
Hastings' Dictionary of the Bible (1898)
U'RIM and THUM'MIM (light and perfection) denote some part of the high priest's apparel. In Ex 28:15-30 it is prescribed that the Urim and Thummim shall be placed beneath the breastplate, in order to be on the high priest's heart when he goes in before the Lord; and when Aaron was arrayed, Moses himself put the Urim and Thummim into the breastplate. Lev 8:8. In the blessings of Moses he speaks of the Urim and Thummim as the crowning glory of the Levite tribe; and when Joshua is solemnly appointed to succeed him.
Num 27:21, the high priest, Eleazar, is said to ask counsel for him after the judgment of Urim. But nowhere in Scripture are the Urim and Thummim described, and, as Jewish tradition can give no information, we do not know what they really were.
Hitchcock's Bible Names (1869)
lights; fires