a river in E Africa, flowing NNW from Lake Tana in Ethiopia into the Nile at Khartoum: a tributary of the Nile. About 950 miles (1530 km) long.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
British Dictionary definitions for blue nile
a river in E Africa, rising in central Ethiopia as the Abbai and flowing southeast, then northwest to join the White Nile. Length: about 1530 km (950 miles)
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012