The Hebrew word Ulai (אוּלַי) refers to the Ulai Canal (or river) in the region of ancient Persia (modern Khuzestan, Iran). The name appears as the setting of the prophet Daniel's second vision, where he stood "by the Ulai Canal" and received a revelation about empires to come.
The Ulai river is significant as the geographic setting of Daniel's vision of the ram and the goat (Daniel 8), one of the most precise prophetic passages in the Bible. The ram represents Medo-Persia; the goat, Greece. The precision of the location — an actual, verifiable Persian waterway — grounds the vision in historical reality and underscores God's sovereignty over world empires. This vision was fulfilled with remarkable accuracy through Alexander the Great.