Ulai

Boyd’s Bible Dictionary:

(pure water). A river in the province of Elam, where the palace of Shushan stood, on whose banks Daniel saw the vision of the ram and the he-goat (Dan. 8:2-16).

Concise Bible Dictionary:

River flowing near to the city of Shushan, where Daniel saw himself in a vision (Dan. 8:2, 16). It is judged to be the Eulaeus of the Greeks and Romans. Identified by some with the Kerkhah, an affluent of the Tigris, and this agrees with the upper Eulaeus. Others have traced it to the Kuran, another affluent of the Tigris, and this agrees with the lower Eulaeus; but at one part a branch of the former once ran into the latter.

Strong’s Dictionary of Hebrew Words:

Transliteration:
’Uwlay
Phonic:
oo-lah’ee
Meaning:
of Persian derivation; the Ulai (or Eulaeus), a river of Persia
KJV Usage:
Ulai

Jackson’s Dictionary of Scripture Proper Names:

my leaders (mighties)

Potts’ Bible Proper Names:

Muddy water; strength; pool; senseless:―a river of Persia, Dan. 8:2. {Aqua lutosa}