Noun

1. The sacred devices (not always physical) used for casting lots
   • 1671, John Milton, Paradise Regained:

     […] / Should kings and nations from thy mouth consult, / Thy counsel would be as the oracle / Urim and Thummim, those oraculous gems / On Aaron’s breast, or tongue of Seers old / —

2. A set of seer stones bound by silver bows into a set of spectacles, that founder Joseph Smith, Jr. said he found on the hill Cumorah and used to interpret the golden plates.