תֻּמִּים Tummîym (H8550)

perfections, i.e. (techn.) one of the epithets of the objects in the high-priest's breastplate as an emblem of complete Truth

Thummim = "perfection" 1) stones provided for the means of achieving a sacred lot 1a) used with the Urim, the will of God was revealed

plural of תֹּם (H8537);