DONGA, a Bantu word for a ravine, narrow watercourse or gully formed by the action of water. Adopted by the European residents of South Africa from the Kaffirs, the use of the word has been extended by English writers to ravines or watercourses of the nature indicated in various other parts of the world. It is almost equivalent to the Arabic khor, which, however, also means the dry bed of a stream, or a stream flowing through a ravine. The Indian word nullah (properly a watercourse) has also the same significance. The three words are often used interchangeably by English writers.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)