what is the definiton of nile river
â¢ NILE RIVER (noun). The noun NILE RIVER has 1 sense: 1. the world's longest river (4150 miles); flows northward through eastern Africa into the Mediterranean; the Nile River valley in Egypt was the site of the world's first great civilization. Familiarity information: NILE RIVER used as a noun is very rare.Dictionary entry details.he world's longest river (4150 miles); flows northward through eastern Africa into the Mediterranean; the Nile River valley in Egypt was the site of the world's first great civilization. Classified under: Nouns denoting natural objects (not man-made).