any of the fat-soluble vitamins, including calciferol and cholecalciferol, occurring in fish-liver oils (esp cod-liver oil), milk, butter, and eggs: used in the treatment of rickets and osteomalacia
vitamin D in American English
any of several fat-soluble vitamins that are essential for increased absorption of calcium and phosphorus from the intestinal tract, found in fish-liver oils, milk, egg yolk, etc. or produced by irradiation of provitamins
; specif.,
a.
vitamin D2
see also ergocalciferol
b.
vitamin D3
see also cholecalciferol
c.
vitamin D4, C28H45OH, produced by irradiation of a derivative of ergosterol
d.
vitamin D5, C29H47OH, produced by irradiation of a derivative of sitosterol
, a deficiency of vitamin D tends to cause rickets