One of the two principal headwaters of the River Nile. Rising from Lake Tana in north-west Ethiopia, it flows some 1,600 km (1,000 miles) southwards then north-westwards into Sudan, where it meets the White Nile at Khartoum.
Definition of Blue Nile in US English:
Blue Nile
proper noun
One of the two principal headwaters of the Nile River. It rises from Lake Tana in northwestern Ethiopia and flows about 1,000 miles (1,600 km) south and then northwest into Sudan, where it meets the White Nile at Khartoum.