It is a naturally moist tropical forest or savanna that stretches along the coast and borders the Sahel belt in the north.
The Portuguese term emerged in the mid-15th century to refer to the lands inhabited by the Guineus, a generic term used by the Portuguese to refer to the "black" African peoples living south of the Senegal River (in contrast to the "tawny" Sanhaja Berbers, north of it, whom they called Azenegues).
[2][3][4] It is believed the Portuguese borrowed Guineus from the Berber term Ghinawen (sometimes Arabized as غِنَاوَة Guinauha or Genewah) meaning "the burnt people" (analogous to the Classical Greek Aithiops, "of the burned face").
A competing theory, first forwarded by Leo Africanus in 1526,[7] claims that "Guinea" is derived from Djenné (which he refers to as Gheneo, Genni and Ghinea),[8] the great interior commercial city on the Upper Niger River.
[10] Conversely, it remains possible that both Ghana and Djenné themselves owe their original city names to the Berber appellation for the blacks that lived there.
The extensive trade in ivory, gold, and slaves made the region wealthy, with a number of centralized kingdoms developing in the 18th and 19th centuries.
Lower Guinea is one of the most densely populated regions of Africa, covering southern Nigeria, Benin, Togo and stretching into Ghana.