n :  any or all of several fat-soluble vitamins chemically related to steroids, essential for normal bone and tooth structure, and found esp. in fish-liver oils, egg yolk, and milk or produced by activation (as by ultraviolet irradiation) of sterols: as  a  :  CALCIFEROL  b  :  CHOLECALCIFEROL - called also sunshine vitamin  .
 
 
 
Similar sounding terms:  vitamin D₃  vitamin D₂ 
 
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