Fountains in Islamic art and architecture exhibit considerable variation, both in terms of the etymologies of the various words for "fountain" and the physical forms, facts that may reflect the structure's multiple linguistic and architectural sources. Etymologically, some of the terms that have been used to refer to fountains-including ʿayn (spring), salsabīl (sacred spring), and kaʾs (cup or basin)-are Qurʾānic; others-including dūlāb (rotating fountain), çeshme (water jet), and shādirwān or chādar (inclined plane fountain)-have a Persian etymology; and one later term, fisqiyya (small basin with