Urim \U"rim\, n. [Heb. ?r[=i]m, pl. of ?r, fire ?r light.]

A part or decoration of the breastplate of the high priest among the ancient Jews, by which Jehovah revealed his will on certain occasions. Its nature has been the subject of conflicting conjectures.

Thou shall put in the breastplate of judgment the Urim and the Thummim. --Ex. xxviii. 30.

And when Saul inquired of the Lord, the Lord answered him not, neither by dreams, nor by Urim, nor by prophets. --1 Sam. xxviii. 6.

Note: Professor Plumptre supposes the Urim to have been a clear and colorless stone set in the breastplate of the high priest as a symbol of light, answering to the mystic scarab in the pectoral plate of the ancient Egyptian priests, and that the Thummim was an image corresponding to that worn by the priestly judges of Egypt as a symbol of truth and purity of motive. By gazing steadfastly on these, he may have been thrown into a mysterious, half ecstatic state, akin to hypnotism, in which he lost all personal consciousness, and received a spiritual illumination and insight.

Source: Webster's Revised Unabridged Dictionary (1913)