A donga is a crack in the soil, a ditch, steep-sided gully or dry ravine caused by water erosion, often exacerbated by over-intensive farming and erratic rainfall. After drought and livestock have stripped away the binding vegetation, soil is easily eroded by occasional heavy rains.

A donga can be small enough for a child to step across, or large enough for a truck to fall into. It is not uncommon for drivers to refer to washed out country roads as having dongas.

A rocky ravine on the side of a mountain is generally not called a donga but a kloof. A donga is a fresh scar on bare soil.

This word is mostly found in South African English and in Afrikaans, and is a borrowing from the Bantu languages.

The Australian phrase "Dry as a dead dingos donga." appears to be unrelated. In this vocabulary, donga (also spelled "donger") appears to mean dong.