Main Entry: vitamin D

Function: noun

Date: circa 1921

: any or all of several fat-soluble vitamins chemically related to steroids, essential for normal bone and tooth structure, and found especially in fish-liver oils, egg yolk, and milk or produced by activation (as by ultraviolet irradiation) of sterols: as aor vitamin D2 \-ˈdē-ˈtü\ : calciferol bor vitamin D3 \-ˈdē-ˈthrē\ : cholecalciferol