The English name Nile and the Arabic names en-Nîl and an-Nîl both derive from the Latin Nilus and the Ancient Greek Νεῖλος.  Beyond that, however, the etymology is disputed. Homer called the river Αἴγυπτος, Aiguptos, but in subsequent periods, Greek authors referred to its lower course as Neilos; this term became generalised for the entire river system. Thus, the name may derive from Ancient Egyptian expression nꜣ rꜣw-ḥꜣw(t) (lit. ‘the mouths of the front parts’), which referred specifically to the branches of the Nile transversing the Delta, and would have been pronounced ni-lo-he in the area around Memphis in the 8th century BCE. Hesiod at his Theogony refers to Nilus (Νεῖλος) as one of the Potamoi (river gods), son of Oceanus and Tethys.

Another derivation of Nile might be related to the term Nil (Sanskrit: नील, Egyptian Arabic: نيلة), which refers to Indigofera tinctoria, one of the original sources of indigo dye. Another may be Nymphaea caerulea, known as “The Sacred Blue Lily of the Nile”, which was found scattered over Tutankhamen’s corpse when it was excavated in 1922.

Another possible etymology derives from the Semitic term Nahal, meaning “river”. Old Libyan has the term lilu, meaning water (in modern Berber ilel means sea).