The Collaborative International Dictionary of English v.0.48:

Euphrates \Euphrates\ prop. n.
   an Asia river flowing into the Persian Gulf.

   Syn: Euphrates River.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

Euphrates
    n 1: a river in southwestern Asia; flows into the Persian Gulf;
         was important in the development of several great
         civilizations in ancient Mesopotamia [syn: Euphrates,
         Euphrates River]