- a fat-soluble, crystalline, unsaturated alcohol, C28H43OH, occurring in milk, fish-liver oils, etc., produced by ultraviolet irradiation of ergosterol, and used as a dietary supplement, as in fortified milk.Also called vitamin D2.
- a fat-soluble steroid, found esp in fish-liver oils, produced by the action of ultraviolet radiation on ergosterol. It increases the absorption of calcium from the intestine and is used in the treatment of rickets. Formula: C 28 H 43 OHAlso: vitamin D 2
- vitamin D2
- Any of several sterols that are forms of vitamin D, especially ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3). See more at vitamin D.