Urim

Chamber's Twientieth Century Dictionary · 1908 · p. 118

ū′rim, Thummim , thum′im, ns.pl. first mentioned in Exod. xxviii. 30, in connection with the High-priest's breastplate, apparently a pair of objects used at critical junctures as a kind of traditional oracle, but which could not always be counted on for an answer (1 Sam. xxviii. 6).