- (Islam) fasting; one of the five pillars of Islam
- In ecology, a herbaceous border found at the edge of a woodland patch. It is usually found below and farther out from the woodland than the woody shrub mantel and the tree canopy. (See R.T.T.Forman and Michel Godron. Landscape Ecology. 1986. pp. 108-109.)
Arabic صوم (ṣawm, “fasting”).