calciferol
noun
cal·cif·er·ol kal-ˈsi-fə-ˌrȯl 
-ˌrōl
: an alcohol C28H43OH usually prepared by irradiation of ergosterol and used as a dietary supplement in nutrition and medicinally in the control of rickets and related disorders
called also vitamin D2
Example Sentences
Recent Examples on the Web And there's some evidence to back his recommendation up: The NIH says vitamin D—a fat-soluble vitamin known as calciferol and produced naturally by your body—can help strengthen bones, reduce inflammation, and help with immune function. 
Amber Brenza, Health.com, 5 Oct. 2020 Backing up a second here: Vitamin D, aka calciferol, is a fat-soluble vitamin that’s naturally present in a few foods, like fatty fish, beef liver, cheese, and egg yolks, per the National Institutes of Health Office of Dietary Supplements (NIH). Korin Miller, Health.com, 14 Sep. 2020
Amber Brenza, Health.com, 5 Oct. 2020 Backing up a second here: Vitamin D, aka calciferol, is a fat-soluble vitamin that’s naturally present in a few foods, like fatty fish, beef liver, cheese, and egg yolks, per the National Institutes of Health Office of Dietary Supplements (NIH). Korin Miller, Health.com, 14 Sep. 2020 Word History
Etymology
calciferous + ergosterol
First Known Use
1931, in the meaning defined above
Medical Definition
calciferol
noun
cal·cif·er·ol kal-ˈsif-ə-ˌrȯl, -ˌrōl
: an alcohol C28H43OH usually prepared by irradiation of ergosterol and used as a dietary supplement in nutrition and medicinally especially in the control of rickets
called also ergocalciferol, viosterol, vitamin D, vitamin D2
see drisdol