OASIS (Gr. ὄασις, the name given by Herodotus to the fertile spots in the Libyan desert: it probably represents an Egyptian word, cf. Coptic ouahe, ouih, to dwell, from which the Egyptian Arabic wā is derived), a fertile spot surrounded by desert. For example, where the high plateau of the Libyan desert descends into a longitudinal valley between Syrtis and the Nile delta there are a few spots where the water comes to the surface or is found in shallow wells. It may come to the surface in springs, upon the artesian principle, or it may collect and remain in mountain hollows. These areas are of small extent and are closely cultivated, and support thick forests of date-palms. All kinds of tropical vegetables, grains and small fruits grow under cultivation, and land is so precious in these limited areas of great richness and fertility that very narrow pathways divide each owner’s plot from his neighbour’s. Wherever oases are found they present similar features, and are naturally the halting-places and points of departure of desert caravans.