Thummim

Concise Bible Dictionary:

See URIM.

Strong’s Dictionary of Hebrew Words:

Transliteration:
Tummiym
Phonic:
toom-meem’
Meaning:
plural of 8537; perfections, i.e. (techn.) one of the epithets of the objects in the high-priest's breastplate as an emblem of complete Truth
KJV Usage:
Thummim

Jackson’s Dictionary of Scripture Proper Names:

perfections

Potts’ Bible Proper Names:

Perfections; judgment; completeness:―an object in the high-priest’s breastplate as an emblem of Truth, Exod. 28:30. {Perfectiones}