The Color Purple vocabulary

an enormous tract of territory, longer than it is wide, has sunk bodily far below the level of the table-land, forming a deep trough, of the total area approaching that of Europe, in which are found the Great Lakes with their own river system, and, ultimately, the source of the Nile.

^{Cecil Scott Forester. The African Queen, p.62 (1935)}

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a series of contiguous geographic trenches, approximately 6,000 kilometres (3,700 mi) in total length, that runs from the Beqaa Valley in Lebanon in Asia to Mozambique in southeastern Africa. While the name continues in some usages, it is rarely used in geology nowadays as it is considered an imprecise merging of separate though related rift and fault systems.

Today, the term is most often used to refer to the valley of the East African Rift, the divergent plate boundary which extends from the Afar Triple Junction southward across eastern Africa, and is in the process of splitting the African Plate into two new separate plates. Geologists generally refer to these incipient plates as the Nubian Plate and the Somali Plate.