Qanat is the Arabic word for canal, as in Qanat as-Suwais, the Suez Canal, but it also specifically refers to an underground canal, built connecting the bottom of a well uphill with an area to be irrigated downstream from it.
In the Sahara Desert they are known by the Berber name foggara. Though the Sahara is now too dry to support much agriculture, this is a recent development in historical terms, and ancient foggaras or their remains still exist. In the East, such as Afghanistan, they are known by the Persian term qarez (sometimes romanized karez). An engineer who excavates a qanat is called a muqanni.