is probably a word of Aryan origin, signifying “the good and abounding river.” It is most frequently denoted in the Bible by the term “the river.” The Euphrates is the largest, the longest, and by far the most important of the rivers of western Asia. It rises from two chief sources in the Armenian mountains and flows into the Persian Gulf. The entire course is 1,780 miles, and of this distance more than two-thirds (1,200 miles) is navigable for boats. The width of the river is greatest at the distance of 700 or 800 miles from its mouth—that is to say, from its junction with the Khabour, to the village of Werai. It there averages 400 yards. The annual inundation of the Euphrates is caused by the melting of the snows in the Armenian highlands. It occurs in the month of May. The great hydraulic works ascribed to Nebuchadnezzar had as their chief object controlling the inundation. The Euphrates is first mentioned in Scripture as one of the four rivers of Eden (Genesis 2:14). We next hear of it in the covenant made with Abraham (Genesis 15:18). During the reigns of David and Solomon it formed the boundary of the promised land to the northeast (Deuteronomy 11:24; Joshua 1:4). Prophetical reference to the Euphrates is found in (Jeremiah 13:4-7; 46:2-10; 51:63; Revelation 9:14; 16:12) “The Euphrates is linked with the most important events in ancient history. On its banks stood the city of Babylon; the army of Necho was defeated on its banks by Nebuchadnezzar; Cyrus the Younger and Crassus perished after crossing it; Alexander crossed it, and Trajan and Severus descended it.”–Appleton’s Cyc.
Smith's Bible Names Dictionary (1866)