Etymology

Niger

African nation, named for the river Niger, mentioned by that name 1520s (Leo Africanus), probably an alteration (by influence of Latin niger "black") of a local Tuareg name, egereou n-igereouen, from egereou "big river, sea" + n-igereouen, plural of that word. Translated in Arabic as nahr al-anhur "river of rivers."

Definitions of Niger

Niger (n.)
an African river; flows into the South Atlantic;
Synonyms: Niger River
Niger (n.)
a landlocked republic in West Africa; gained independence from France in 1960; most of the country is dominated by the Sahara Desert;
Synonyms: Republic of Niger
From wordnet.princeton.edu